I've used Gear Lever for a while, but unfortunately the lead of the Appimage project refuses to update for Fusev3 so eventually support for the format will end in most distros as Fusev2 is considered unmaintained and a potential security vuln. I know Fedora has been discussing dropping it.
That said, Flatpaks are nice these days and my preferred format. I avoid .rpm/deb/etc as installing apps with root permissions is poor security.
