And for the record Flatpak does not have any such limitation - while many people use Flathub to host flatpal repos, there are many more Flatpak repos available,

And for the record Flatpak does not have any such limitation - while many people use Flathub to host flatpal repos, there are many more Flatpak repos available, including Distro hosted ones (Fedora has a system for building Flatpaks from Fedora RPMs and hosting the resulting Flatpak repos).