Black616Angel

Doesn’t look like it, but you can be the one writing one.

Okay, the others are a little short for what you need.

Your VPN needs it’s own DNS. With that DNS you can route the traffic internally from the VPN subnet to the server. Then you can set the server up to only take requests from that subnet either via firewall or the reverse proxy.

This is the way! I also have a synapse with this ansible playboy up and running and it works like a charm.

Look into Periodical as well, it’s on fdroid and completely local. It also shows when the next period should be and works better than some closed source apps.