There is currently no higher version then Android 9 available for AOSP version on Amlogic devices running S905X2,X3,Y2 and 922X.
Nvidia uses Android TV, which currently does have a higher version of Android, but that's because its Android TV.
If you compare AOSP changes on 10 and 11 to 9
There are almost 0 benefits for TV boxes, its all for Phones.