For screenshots there are currently two competing approaches. GNOME and KDE have opted for dbus interfaces (e.g org.gnome.Shell.Screenshot) and Sway has opted for Wayland protocol extensions (zwlr_screencopy_manager_v1). I think the former is more maintainable because dbus interfaces are accessible by pure cli tools where grim and wl-clipboard have to create dummy wayland surfaces just to talk to the compositor.

At least everyone agrees on the notification dbus interface and the tooling is super mature.