I built my own nostr notifications solution...

Although its not a NIP or a protocol. its just a simple Bun server that is designed to run on your server (Umbrel) and uses ntfy.sh to send the notifications.

https://github.com/hzrd149/nostr-secretary

It still needs more work but its installable on your Umbrel if you add my app store https://github.com/hzrd149/umbrel-community-app-store