Blurry apps come from xwayland compatibility. Firefox and alacritty (or other terminal like wezterm or kitty) have native wayland, with no blurry check Archwiki for example HiDPI. With Spotify, live with it or use spot (gtk client). Hopefully next gnome release incorporate something like plasma, and then ctrl+ native in spotify increase its size.
Well, but XWayland apps should not be blurry now!