Echo on this request.
The flatpak image of cider is out of date. I'm unsure why you would develop an AppImage. No one wants to install the requirements to run AppImages on their systems. Obviously https://build.opensuse.org/is fantastic for building RPM's for RedHat/Fedora/OpenSUSE as well as DEB packages for Debian based systems.
Using OBS + Flatpak, you are appealing to the widest Linux community with the minimal required effort. The current RPM is limited to Fedora based systems and fails on OpenSUSE for example.