[DiapDealer]

Make sure you've checked the box to use the bundled Python in Sigil's preferences.The TagMechanic plugin is one of many different plugins I've used to test AppImage functionality on several different distros. It should work fine.

NOTE: after checking the "Use Bundled Python" you may need to restart the Sigil AppImage.

I've no experience with AppImageLauncher. The version available for Arch is incompatible with the latest built AppImages that use a static runtime to get around fuse2 unavailability/incompatibility. I can't compile it myself either. There's a lot of work to be done with AppImageLauncher for it to be usable on many modern Linux systems in my opinion (the least of which is updating to work with Qt6). I'm honestly not sure it's worth the effort at this point.