When I needed this I reached for whatever generic rtmp cameras were well rated. Blocked them from external access (including outgoing!) at the firewall level and used Zoneminder and some custom scripts to monitor.

SMTP is how emails are sent between mailservers too

I mean, there’s audiobookshelf, but that’s… Not for that. Idk, it might work.

I tried radicale. Nextcloud is easier to manage. That’s what I recommend.

Good to know, thank you.