Not a reviewer so just my two cents…
Related thread: Allow other Snap apps to use steam-support, instead of just Steam
Specifically:
Note that as a last resort you can also make the steam-support interface available for usage by publishing the snap via external channels(e.g. GitHub Releases), declaring the interface in the plugs section of the Snapcraft project file, and require the user to manually connect the interface after detecting the missing of the connection. This will also disable the auto-update mechanism so you’ll also need to implement update checking functionality if not already available.