I haven't tried it, but looking at the code, it talks to xdp to setup the screencast session and then gstreamer with the pipewiresrc to record it. It should work on any compositor with an xdp implementation that supports the Screencast protocol. KDE's does.
Are you sure it hangs and doesn't just show a dialog somewhere for you to select which screen to cast / give it permission to screencast?
As in it hangs when you launch it, not that it launches successfully but then hangs when you press the Record button? Probably a more fundamental windowing problem than the screencasting interface interaction then.
The GNOME screen recorder works the best out of all the ones I've tried. It allows you to record a selected part of the screen as well, which Blue Recorder doesn't
Looking at the source code, this ui can handle x11 or wayland, but wayland can only do window recording or monitor recording, for x11 it's all just handed over to ffmpeg which can handle x,y,width,height input variables.
A few weeks ago, I tried Blue Recorder just because Gnome's Screen Recorder gave out some static when recording a certain area. IIRC, in Blue Recorder I can't even do recording a selected area, maybe because I am on wayland.
Interesting. On wlroots compositors, it is easier to capture a region than a window, so many screen recording tools that target wlroots (for example wl-recorder) support regions but not windows.
