Hey there!
Got a generic AndroidTV box (branded as "MORTAL") from AliExpress out of curiosity. It has suspicious applications baked in that cannot be disabled, so I want to flash it with clean custom firmware.
Chipset is RK3518, wifi is AIC8800D80, PCB is DR822.R1.1.1.C6.02.V1.1.3.260526.
Very happy to find your work, as Armbian seemed like the best bet here. Going to try out your build in the next few days and report back here.