Flameshot works on Wayland (atleast on KDE)
Gnome is just being stupid in hardcoding an exception for only its own tool under the guise of privacy.
And yeah, it's complicated, but it's fast for power users. Maybe it's no frills design makes it appear more complicated and as a other comment states, maybe there's a way to uncomplicate it (but I totally understand if you don't want to use it)
Looks good (the extension). Any other good tiling extensions with keyboard and GUI support? I would like to explore a few to see which one works well for me