Cheers for those tips, but it's unfortunate to read yours is deteriorating. TBH, I had no idea until today (looking at mine to install) of the current incompatibility of glass screen protectors with imbedded fingerprint scanners. Given how completely sh!te the scanner is on this phone I'd be tempted to do what some do and go with a glass protector and just don't bother using the finger scanner; but, that said, I'd hate to have to go back to entering a password for internet banking and Lastpass, given face ID ain't (and shouldn't be) an option...
If I have no luck with these screen protectors I think I'll go to solely a flip case to protect the screen.