OP here. Thanks for all your input! It’s really an embarrasment of riches which will take me some time to navigate. But thats part of the fun, right? Again, thanks everyone.

PA-220 fw for internet access. An old workhorse, Synology DS1812+, for filesharing. A mac mini with Ubuntu running Plex and Roon also hosting Dashy in docker. A Hwg-ste to measure temp in my cabinet. I host a RIPE probe. An RPI4 running Zabbix. My next project is moving from PA-220 to something in the 400 series (probably 415) so I can upgrade to newer PANOS.

I use Roon right now. Its great if you want to tinker around. I also have Plex which is more plain for music but works well enough.

This. For exactly this reason.

Roon is self-hosted but not open spurce. Incredible at playing music, beautiful UI etc. Not free but best in class imo. https://roon.app/en/