The largely-unmaintained Python 3 port of syncthing-gtk already failed to start on Python 3.11 since it removed obsolete methods like bind_textdomain_codeset(): https://github.com/void-linux/void-packages/issues/40430

Though this project isn't exactly in the best shape, having prior bugs: https://salsa.debian.org/debian/syncthing-gtk/-/issues/2