Gpodder-compatible syncing server

AntennaPod is a popular podcast client for Android. It can save/sync the subscriptions and the played episodes using gpodder.net. However, that website seems abandoned and broken, so the alternative is to self-host your own syncing server.

There are several options:

It would be great to have a good LSIO image for at least one of these three syncing servers.

Sidenote: There is some effort to make a standard API for podcast synchronization, creating a specification beyond just “copying over whatever gpodder does”. https://openpodcastapi.org/