Couple of days ago I lost the connection to ntfy.sh, so we started talking on the #selfhosted matrix.org chat about notifications and ntfy, I started selfhosting ntfy and then stratself pointed out one can also use Conversations as a provider.

Long story short, I tried it and it works. This is the config for someone hosting xmpp with prosody and using apache reverse proxy. The original post of stratself gives the config with ejabberd and Caddy, it's linked in the beginning.

Amazing all you can do!