Android 10 SDK is still pre release from Amlogic, and was only given as Android TV SDK, not AOSP.
It still needs a lot of work
It took 4 SDK updates from Amlogic before Android 9 became stable.
They're on their 6th SDK version now 01-17-20, for Android 9.
Plus what is the reason for wanting Android 10?
As I have not seen any added benefits listed for Android 10 from Google that would benefit a TV Box.