Removing the factory fitted screen protector on the Fold 3 will not void your 2 year manufacturing warranty.
But If you damage the screen while removing the factory fitted screen protector then that will void your warranty.
I've seen multiple YouTube videos and spoken with people who have removed it and all have looked and said it's an easy process. Just take care.
Yes the phone Folds but take into account it does not fold tightly shut so dust etc can get in onto the screen.
Some have reported that removing the screen protector makes the phones display nicer to use and less of a fingerprint magnet.
Some have fitted the Whitestone Dome Glass Screen Protector after removing the factory fitted screen protector, and like this more as its glass instead of plastic. Using one wont invalidate your manufacturing warranty.
Personally I'm leaving mine on the phone as I find it good quality and does not feel like plastic to me, it feels like Glass.
I'll only replace it through wear and tear through continued usage if I have to.
Removing the factory fitted screen protector won't change the way the crease looks.
However after some time of using the phone and looking at the screen display head on i.e the natural way to look at the inner screen the crease mostly blends in, and I basically look past it.
I now only really notice it when I'm touching the display to navigate around and my finger slides across the crease.
Hope that helps.
Daily Driver > Samsung Galaxy s²² Ultra 256Gb.
Samsung Gear s³ Frontier Watch.
Samsung Galaxy Watch⁴ Classic.
The advice I offer is my own and does not represent Samsung’s position.
I have no affiliation with Samsung.