Usually I only have complaints and suggestions, but in this thread I actually wanted to give some kudos.
When I connect my Tab s8 ultra as an external display and I enable touch input, I am actually able to use my S-pen as a stylus, and even the s-pen button works ! Meaning that you erase by holding it as you "write" on the screen.
Not sure if this is something you put work into, but it's nice to see!
(almost feels like I have an Android app for PDF-xchange editor
)