On a Debain sid install I was somehow recently bumped from Gnome3 on X11 toi Gnome3 on wayland. Chromium and Qt apps got broken scaling; I solved it by forcing the session to be Gnome3 on X11.
This is just anecdote of course! I would have liked to dig more into it and figure things out, but honestly I just had too much to do and chose whatever was working for me.