I think devs can use Gtk if they're developing for Linux or don't mind using pyGtk for multi-platform, use Qt or Flutter otherwise if they're going multi-platfo

I think devs can use Gtk if they're developing for Linux or don't mind using pyGtk for multi-platform, use Qt or Flutter otherwise if they're going multi-platform, make sure everything follows freedesktop specifications, and then just pack it to Flatpak, test it for Gnome and KDE... then just tell everyone whose DE doesn't support it to just deal with it. Heck, many apps are web-based and uses electron anyways, and those are generally multiplatform anyways. I think if whatever app they make/port worrks via Flatpak, it should work on all/most modern distro.