I don’t know how many users of the beta Flatpak read this forum – in fact, we have no idea how many users there are of the beta at all – but if there are any, perhaps they could weigh in.
For all other platforms, the project provides a) numbered point releases (1.102, 2.0, 2.1 etc.) every few months and b) nightly builds available from GitHub.
Flatpak is the exception here, because we decided to use Flathub’s beta repository to publish “cutting edge” builds, and they explicitly don’t want nightly releases, so the “beta” Flatpak receives releases less frequently than the nightlies (sometimes once a week, sometimes once a month).
Nowadays the automatic building and testing infrastructure on GitHub is building a Flatpak every time new code is added, just like for the other platforms. So we have nightly Flatpak builds now, it’s just that we aren’t making them available.
It’s really very easy to host a Flatpak repository and can even be done using GitHub pages.
I’m thinking that we retire the beta Flatpak and instead make a self-hosted nightly one available that we update in a fully automated fashion. From a user perspective it would be no more difficult to set up our nightly repo than the Flathub beta repo, which is never enabled by default and therefore always requires some setup.