After using the S8, Note 8, S9+ and now the S20, I can tell u with confidence that no tempered glass will work properly with curved screens. They tend to peel off, or the edges don't function properly. u can try a screenguard (the plastic films). they won't have any issues but again, if u put a cover, they"ll peel off.
I usually don't put any protection on the screen. the S20 series has Gorilla Glass 6, so that's some assurance for me.
I have used Rs 80 hammer gaurd (plastic screen protector) and now I am using Super-D tempered glass protector on my A71.
Both worked well with Soft silicon TPU case. Edge to edge curved screen protector will create problem with normal cases. You need to buy cases specifically designed to work with tempered glass. Or use without case and screen protector. But even Gorilla glass 7 will scratch with regular use.
