Meron custom rom para mga Android TV box.. I suggest ATVexperience (android 9)since may forum support sila.
Just make sure to check your device first para di ka magkaproblema/bricked.
Check Device specs first
EG:
CPU : S905X p212
Ram: 1GB /2G /3GB/4GB
Rom: 8GB/16GB/32GB
Board : p212 S905QX V1.0
EMMC/NAND: SEC 812 samsung
Just make sure you do your research first.. I owm 2 devices
MXQ pro 4k s905x 1/8 (4 year-old device still kicking)
x96 mini s905w 2/16 (1 year-old)
yung MXQ , CoreELEC firmware(linux i believe) KODI
yung x96 mini ATVexperience
and compare sa stock Android ng device.. mas smooth kapag gumamit ka ng custom ROM
hope this will help