I think evince will be eventually dropped by GNOME but there is time for that. While papers is porting things to GTK4 and adding some great features, it still has a long way to go in performance and optimisation. Currently it is more than twice as slow to open a pdf when compared to evince. Also scrolling performance is not optimised as it will stop mid scroll for things to render. Well it is only a new project so hopefully all this will be fixed. I am still using papers so that I can report any bugs that I run into