For using MBIM, you can issue the commands (of put it in a boot script):
ifconfig wwan0 up
mbimcli -d /dev/wwan0mbim0 --query-subscriber-ready-status --no-close
mbimcli -d /dev/wwan0mbim0 --query-registration-state --no-open=3 --no-close
mbimcli -d /dev/wwan0mbim0 --attach-packet-service --no-open=4 --no-close
mbimcli -d /dev/wwan0mbim0 --connect=access-string='<YOUR ISP APN STRING>' --no-open=5 --no-close
udhcpc -q -f -i wwan0 -x lease:864000
You need to install kmod bbr and paste the following lines into /etc/sysctl.conf
net.ipv4.tcp_congestion_control = bbr
net.ipv4.tcp_adv_win_scale = -2
net.ipv4.tcp_notsent_lowat = 131072
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_mtu_probing = 1
net.ipv4.tcp_sack = 0
net.core.netdev_max_backlog = 1048576
net.core.rmem_max = 16777216
net.core.somaxconn = 65535
net.core.wmem_max = 16777216
net.ipv4.ip_local_port_range = 1024 65535
net.ipv4.tcp_fin_timeout = 5
net.ipv4.tcp_max_orphans = 1048576
net.ipv4.tcp_max_syn_backlog = 20480
net.ipv4.tcp_max_tw_buckets = 400000
net.ipv4.tcp_no_metrics_save = 1
net.ipv4.tcp_rmem = 4096 87380 16777216
net.ipv4.tcp_synack_retries = 2
net.ipv4.tcp_syn_retries = 2
net.ipv4.tcp_tw_reuse = 1
Try these tweaks by pasting the following lines into /etc/rc.local
echo 524288 > /sys/module/nf_conntrack/parameters/hashsize
echo 'on' > /sys/devices/platform/soc/11280000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/power/control