That should be handled in its own topic, but from what I see, the interface is up (just with no clients connected at this point); luci can be a bit confusing in this regard (signal and wireless rate can only be established if there are connected clients to this radio).
The install instructions from the git link need to be added to the device page. I copied them below for anyone else that finds this article.
Update firmware instructions:
Please update the firmware via U-Boot web UI (by default at 192.168.1.1, following instructions found at https://docs.gl-inet.com/en/3/troubleshooting/debrick/).
Normal sysupgrade, either via CLI or LuCI, is not possible from stock firmware.
Please do use the *gl-b2200-squashfs-emmc.img file, gunzipping the produced *gl-b2200-squashfs-emmc.img.gz one first.