got it working,
firmware is needed from https://anduin.linuxfromscratch.org/sources/linux-firmware/mediatek/
BT_RAM_CODE_MT7961_1_2_hdr.bin
WIFI_RAM_CODE_MT7961_1.bin
WIFI_MT7961_patch_mcu_1_2_hdr.bin
and in kernel CONFIG_MT7921U=m
very good speed.
LibreELEC:~/.config/firmware/mediatek # iperf3 -c speedtest.ownit.se
Connecting to host speedtest.ownit.se, port 5201
[ 5] local 192.168.5.177 port 57168 connected to 84.55.107.2 port 5201
[ ID] Interval Transfer Bitrate Retr Cwnd
[ 5] 0.00-1.00 sec 53.4 MBytes 446 Mbits/sec 0 1.62 MBytes
[ 5] 1.00-2.00 sec 65.0 MBytes 547 Mbits/sec 0 1.62 MBytes
[ 5] 2.00-3.00 sec 67.5 MBytes 566 Mbits/sec 0 1.62 MBytes
[ 5] 3.00-4.00 sec 66.2 MBytes 556 Mbits/sec 0 1.62 MBytes
[ 5] 4.00-5.00 sec 65.0 MBytes 545 Mbits/sec 0 1.62 MBytes
[ 5] 5.00-6.00 sec 63.8 MBytes 535 Mbits/sec 0 1.62 MBytes
[ 5] 6.00-7.00 sec 66.2 MBytes 556 Mbits/sec 0 1.62 MBytes
[ 5] 7.00-8.00 sec 62.5 MBytes 523 Mbits/sec 0 1.62 MBytes
[ 5] 8.00-9.00 sec 66.2 MBytes 557 Mbits/sec 0 1.62 MBytes
[ 5] 9.00-10.00 sec 65.0 MBytes 545 Mbits/sec 0 1.62 MBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.00 sec 641 MBytes 538 Mbits/sec 0 sender
[ 5] 0.00-10.01 sec 639 MBytes 536 Mbits/sec receiver
iperf Done.