you can install the 2 dependencies manually until they are added
opkg install http://downloads.openwrt.org/releases/21.02.2/packages/arm_cortex-a7/base/libmbedtls12_2.16.12-1_arm_cortex-a7.ipk
opkg install http://downloads.openwrt.org/releases/21.02.2/packages/arm_cortex-a7/base/libevent2-7_2.1.12-1_arm_cortex-a7.ipk
It seems to work ok with the transmission-web gui
No vpn (around 8-12MB/s for a linux mint iso)
Vpn (around 1.6-2MB/s for the same linux mint iso)
Device working as repeater of a wifi 5 network and default transmission parameters. Writing to micro sd (writing speed around 50MB/s, so no bottleneck).
The torrent tests at https://ipleak.net/ and https://torguard.net/checkmytorrentipaddress.php seem to indicate it works ok with the vpn.