I did try to install the driver using this tutorial from openwrt (github --> morrownr How_to_Install_Firmware_for_Mediatek_based_USB_WiFi_adapters.md, but those guys told me it is no original openwrt, so they cannot help me:

here dmesg: pastebin → vPgkpJHK
and the iw-list output:

root@GL-X750:~# iw list
Wiphy phy1
        max # scan SSIDs: 4
        max scan IEs length: 2257 bytes
        max # sched scan SSIDs: 0
        max # match sets: 0
        max # scan plans: 1
        max scan plan interval: -1
        max scan plan iterations: 0
        Retry short limit: 7
        Retry long limit: 4
        Coverage class: 0 (up to 0m)
        Device supports RSN-IBSS.
        Device supports AP-side u-APSD.
        Device supports T-DLS.
        Supported Ciphers:
                * WEP40 (00-0f-ac:1)
                * WEP104 (00-0f-ac:5)
                * TKIP (00-0f-ac:2)
                * CCMP-128 (00-0f-ac:4)
                * CCMP-256 (00-0f-ac:10)
                * GCMP-128 (00-0f-ac:8)
                * GCMP-256 (00-0f-ac:9)
                * CMAC (00-0f-ac:6)
                * CMAC-256 (00-0f-ac:13)
                * GMAC-128 (00-0f-ac:11)
                * GMAC-256 (00-0f-ac:12)
        Available Antennas: TX 0x3 RX 0x3
        Configured Antennas: TX 0x3 RX 0x3
        Supported interface modes:
                 * IBSS
                 * managed
                 * AP
                 * AP/VLAN
                 * monitor
                 * mesh point
                 * P2P-client
                 * P2P-GO
                 * outside context of a BSS
        Band 1:
                Capabilities: 0x11ef
                        RX LDPC
                        HT20/HT40
                        SM Power Save disabled
                        RX HT20 SGI
                        RX HT40 SGI
                        TX STBC
                        RX STBC 1-stream
                        Max AMSDU length: 3839 bytes
                        DSSS/CCK HT40
                Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
                Minimum RX AMPDU time spacing: 8 usec (0x06)
                HT TX/RX MCS rate indexes supported: 0-15
                Bitrates (non-HT):
                        * 1.0 Mbps
                        * 2.0 Mbps (short preamble supported)
                        * 5.5 Mbps (short preamble supported)
                        * 11.0 Mbps (short preamble supported)
                        * 6.0 Mbps
                        * 9.0 Mbps
                        * 12.0 Mbps
                        * 18.0 Mbps
                        * 24.0 Mbps
                        * 36.0 Mbps
                        * 48.0 Mbps
                        * 54.0 Mbps
                Frequencies:
                        * 2412 MHz [1] (23.0 dBm)
                        * 2417 MHz [2] (23.0 dBm)
                        * 2422 MHz [3] (23.0 dBm)
                        * 2427 MHz [4] (23.0 dBm)
                        * 2432 MHz [5] (23.0 dBm)
                        * 2437 MHz [6] (23.0 dBm)
                        * 2442 MHz [7] (23.0 dBm)
                        * 2447 MHz [8] (23.0 dBm)
                        * 2452 MHz [9] (23.0 dBm)
                        * 2457 MHz [10] (23.0 dBm)
                        * 2462 MHz [11] (23.0 dBm)
                        * 2467 MHz [12] (disabled)
                        * 2472 MHz [13] (disabled)
                        * 2484 MHz [14] (disabled)
        Supported commands:
                 * new_interface
                 * set_interface
                 * new_key
                 * start_ap
                 * new_station
                 * new_mpath
                 * set_mesh_config
                 * set_bss
                 * authenticate
                 * associate
                 * deauthenticate
                 * disassociate
                 * join_ibss
                 * join_mesh
                 * remain_on_channel
                 * set_tx_bitrate_mask
                 * frame
                 * frame_wait_cancel
                 * set_wiphy_netns
                 * set_channel
                 * set_wds_peer
                 * tdls_mgmt
                 * tdls_oper
                 * probe_client
                 * set_noack_map
                 * register_beacons
                 * start_p2p_device
                 * set_mcast_rate
                 * testmode
                 * connect
                 * disconnect
                 * channel_switch
                 * set_qos_map
                 * set_multicast_to_unicast
        Supported TX frame types:
                 * IBSS: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * managed: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * AP: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * AP/VLAN: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * mesh point: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * P2P-client: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * P2P-GO: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * P2P-device: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
        Supported RX frame types:
                 * IBSS: 0x40 0xb0 0xc0 0xd0
                 * managed: 0x40 0xd0
                 * AP: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
                 * AP/VLAN: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
                 * mesh point: 0xb0 0xc0 0xd0
                 * P2P-client: 0x40 0xd0
                 * P2P-GO: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
                 * P2P-device: 0x40 0xd0
        software interface modes (can always be added):
                 * AP/VLAN
                 * monitor
        valid interface combinations:
                 * #{ managed } <= 2048, #{ AP, mesh point } <= 8, #{ P2P-client, P2P-GO } <= 1, #{ IBSS } <= 1,
                   total <= 2048, #channels <= 1, STA/AP BI must match, radar detect widths: { 20 MHz (no HT), 20 MHz, 40 MHz }

        HT Capability overrides:
                 * MCS: ff ff ff ff ff ff ff ff ff ff
                 * maximum A-MSDU length
                 * supported channel width
                 * short GI for 40 MHz
                 * max A-MPDU length exponent
                 * min MPDU start spacing
        Device supports TX status socket option.
        Device supports HT-IBSS.
        Device supports SAE with AUTHENTICATE command
        Device supports low priority scan.
        Device supports scan flush.
        Device supports AP scan.
        Device supports per-vif TX power setting
        P2P GO supports CT window setting
        Driver supports full state transitions for AP/GO clients
        Driver supports a userspace MPM
        Device supports active monitor (which will ACK incoming frames)
        Driver/device bandwidth changes during BSS lifetime (AP/GO mode)
        Device supports configuring vdev MAC-addr on create.
        Supported extended features:
                * [ RRM ]: RRM
                * [ CQM_RSSI_LIST ]: multiple CQM_RSSI_THOLD records
                * [ CONTROL_PORT_OVER_NL80211 ]: control port over nl80211
                * [ TXQS ]: FQ-CoDel-enabled intermediate TXQs
Wiphy phy0
        max # scan SSIDs: 16
        max scan IEs length: 199 bytes
        max # sched scan SSIDs: 0
        max # match sets: 0
        max # scan plans: 1
        max scan plan interval: -1
        max scan plan iterations: 0
        Retry short limit: 7
        Retry long limit: 4
        Coverage class: 0 (up to 0m)
        Device supports RSN-IBSS.
        Device supports AP-side u-APSD.
        Supported Ciphers:
                * WEP40 (00-0f-ac:1)
                * WEP104 (00-0f-ac:5)
                * TKIP (00-0f-ac:2)
                * CCMP-128 (00-0f-ac:4)
                * CMAC (00-0f-ac:6)
                * CMAC-256 (00-0f-ac:13)
                * GMAC-128 (00-0f-ac:11)
                * GMAC-256 (00-0f-ac:12)
        Available Antennas: TX 0x1 RX 0x1
        Configured Antennas: TX 0x1 RX 0x1
        Supported interface modes:
                 * managed
                 * AP
                 * monitor
                 * mesh point
        Band 2:
                Capabilities: 0x196f
                        RX LDPC
                        HT20/HT40
                        SM Power Save disabled
                        RX HT20 SGI
                        RX HT40 SGI
                        RX STBC 1-stream
                        Max AMSDU length: 7935 bytes
                        DSSS/CCK HT40
                Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
                Minimum RX AMPDU time spacing: 8 usec (0x06)
                HT TX/RX MCS rate indexes supported: 0-7
                VHT Capabilities (0x33800132):
                        Max MPDU length: 11454
                        Supported Channel Width: neither 160 nor 80+80
                        RX LDPC
                        short GI (80 MHz)
                        RX antenna pattern consistency
                        TX antenna pattern consistency
                VHT RX MCS set:
                        1 streams: MCS 0-9
                        2 streams: not supported
                        3 streams: not supported
                        4 streams: not supported
                        5 streams: not supported
                        6 streams: not supported
                        7 streams: not supported
                        8 streams: not supported
                VHT RX highest supported: 0 Mbps
                VHT TX MCS set:
                        1 streams: MCS 0-9
                        2 streams: not supported
                        3 streams: not supported
                        4 streams: not supported
                        5 streams: not supported
                        6 streams: not supported
                        7 streams: not supported
                        8 streams: not supported
                VHT TX highest supported: 0 Mbps
                Bitrates (non-HT):
                        * 6.0 Mbps
                        * 9.0 Mbps
                        * 12.0 Mbps
                        * 18.0 Mbps
                        * 24.0 Mbps
                        * 36.0 Mbps
                        * 48.0 Mbps
                        * 54.0 Mbps
                Frequencies:
                        * 5180 MHz [36] (23.0 dBm)
                        * 5200 MHz [40] (23.0 dBm)
                        * 5220 MHz [44] (23.0 dBm)
                        * 5240 MHz [48] (23.0 dBm)
                        * 5260 MHz [52] (23.0 dBm) (radar detection)
                        * 5280 MHz [56] (23.0 dBm) (radar detection)
                        * 5300 MHz [60] (23.0 dBm) (radar detection)
                        * 5320 MHz [64] (23.0 dBm) (radar detection)
                        * 5500 MHz [100] (23.0 dBm) (radar detection)
                        * 5520 MHz [104] (23.0 dBm) (radar detection)
                        * 5540 MHz [108] (23.0 dBm) (radar detection)
                        * 5560 MHz [112] (23.0 dBm) (radar detection)
                        * 5580 MHz [116] (23.0 dBm) (radar detection)
                        * 5600 MHz [120] (23.0 dBm) (radar detection)
                        * 5620 MHz [124] (23.0 dBm) (radar detection)
                        * 5640 MHz [128] (23.0 dBm) (radar detection)
                        * 5660 MHz [132] (23.0 dBm) (radar detection)
                        * 5680 MHz [136] (23.0 dBm) (radar detection)
                        * 5700 MHz [140] (23.0 dBm) (radar detection)
                        * 5720 MHz [144] (23.0 dBm) (radar detection)
                        * 5745 MHz [149] (30.0 dBm)
                        * 5765 MHz [153] (30.0 dBm)
                        * 5785 MHz [157] (30.0 dBm)
                        * 5805 MHz [161] (30.0 dBm)
                        * 5825 MHz [165] (30.0 dBm)
                        * 5845 MHz [169] (disabled)
                        * 5865 MHz [173] (disabled)
        Supported commands:
                 * new_interface
                 * set_interface
                 * new_key
                 * start_ap
                 * new_station
                 * new_mpath
                 * set_mesh_config
                 * set_bss
                 * authenticate
                 * associate
                 * deauthenticate
                 * disassociate
                 * join_ibss
                 * join_mesh
                 * remain_on_channel
                 * set_tx_bitrate_mask
                 * frame
                 * frame_wait_cancel
                 * set_wiphy_netns
                 * set_channel
                 * set_wds_peer
                 * probe_client
                 * set_noack_map
                 * register_beacons
                 * start_p2p_device
                 * set_mcast_rate
                 * testmode
                 * connect
                 * disconnect
                 * channel_switch
                 * set_qos_map
                 * set_multicast_to_unicast
        Supported TX frame types:
                 * IBSS: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * managed: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * AP: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * AP/VLAN: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * mesh point: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * P2P-client: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * P2P-GO: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * P2P-device: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
        Supported RX frame types:
                 * IBSS: 0x40 0xb0 0xc0 0xd0
                 * managed: 0x40 0xd0
                 * AP: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
                 * AP/VLAN: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
                 * mesh point: 0xb0 0xc0 0xd0
                 * P2P-client: 0x40 0xd0
                 * P2P-GO: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
                 * P2P-device: 0x40 0xd0
        software interface modes (can always be added):
                 * monitor
        valid interface combinations:
                 * #{ AP, mesh point } <= 8, #{ managed } <= 1,
                   total <= 8, #channels <= 1, STA/AP BI must match, radar detect widths: { 20 MHz (no HT), 20 MHz, 40 MHz, 80 MHz }

        HT Capability overrides:
                 * MCS: ff ff ff ff ff ff ff ff ff ff
                 * maximum A-MSDU length
                 * supported channel width
                 * short GI for 40 MHz
                 * max A-MPDU length exponent
                 * min MPDU start spacing
        Device supports TX status socket option.
        Device supports HT-IBSS.
        Device supports SAE with AUTHENTICATE command
        Device supports scan flush.
        Device supports AP scan.
        Device supports per-vif TX power setting
        Driver supports full state transitions for AP/GO clients
        Driver supports a userspace MPM
        Driver/device bandwidth changes during BSS lifetime (AP/GO mode)
        Device supports static SMPS
        Device supports configuring vdev MAC-addr on create.
        Supported extended features:
                * [ VHT_IBSS ]: VHT-IBSS
                * [ RRM ]: RRM
                * [ SET_SCAN_DWELL ]: scan dwell setting
                * [ CQM_RSSI_LIST ]: multiple CQM_RSSI_THOLD records
                * [ CONTROL_PORT_OVER_NL80211 ]: control port over nl80211
                * [ TXQS ]: FQ-CoDel-enabled intermediate TXQs