I also switched from PaperWM to niri, and I was reluctant to do it, because I really liked not having to configure several different little apps to get a working desktop environment. GNOME comes out of the box with an app launcher, a basic configuration editor, a screen locker, widgets for controlling audio and network, etc. But ultimately, PaperWM was too quirky. For example, sometimes PaperWM and an app would disagree about what size the app's window should be, and the window would resize itself repeatedly. The vertical sizing never worked very well either.