Thank you for the rationale you explained here.
As an example... I don't use chrome/chromium (also a GTK3 app) as my browser, but it was big news this year when they [started supporting XDG Activation](https://chromium-review.googlesource.com/c/chromium/src/+/5280365), allowing links from other apps to bring the browser window to the front, closing a [long-standing issue](https://issues.chromium.org/issues/40747285).
I was under the impression apps (at least on Wayland) needed to be modified to support this behavior. I'll poke around with the GTK folks to see if I can glean anything further in regard to this behavior with Geany under Gnome/Wayland (no X11 or Xwayland here).
EDIT: Oh, yes... GDK3 support [landed](https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/3489) in v3.24