ok, also poking around I think you may need to install Fuse. Because that's needed for AppImages to run. And I think that was removed from ubuntu 22.04. Yeah, I think that might be it. try "sudo apt install libfuse2" and try to run it again. Ahhhhh, Linux! Sorry about this.
OK, this was a doozy. I uploaded a new a super solid appimage that works in mint 21.3, full instructions in the readme. If you're using a high density retina display, the window might be significantly smaller than designed. Spent all day trouble shooting it. But a full fix for window scaling will have to wait till v1.2. If you're using a 1920x1080, display, should be perfectly fine!