I made a test Flatpak build of AudioRelay. Please take note that this is unofficial and I’m not connected in any way with the developer.
To test it:
flatpak install --user flathub org.flatpak.Builder
git clone --branch=audiorelay https://github.com/IverCoder/flathub.git
cd flathub
flatpak run org.flatpak.Builder --user --install --force-clean build-dir net.audiorelay.AudioRelay.yml
To test how the listing would look in an app store, open GNOME Software, KDE Discover, or any storefront of your choice and search for “AudioRelay”, it should show up there once you follow my steps above.
As said, this thing is just like a band-aid solution for a unified Linux build. To achieve true Linux support, AudioRelay’s best bet is to implement the official FreeDesktop portals and support Wayland.