I use a couple of mini pcs in exactly the setup you are talking about. Only downside is throughput. Anything built in is gonna be faster for read write ops, but usb3 is plenty fast for most things including media and data sync. I run Ubuntu with ZFS, and created raid arrays for data redundancy. It works really well. I virtualize using Incus with docker inside of those tiny VMs. It’s awesome.

I use the tp-link EAP615 wall Apps, they are great and run OpenWRT like a champ.

You might look into Netdata, I think it meets your requirements, it’s essentially plug and play, but I believe you can add alerts as well. Been a while since I looked at it, but they’ve put out some big updates lately.

Glad you got Coturn working, what was it?

Haven’t messed with retention and deletion yet. Not enough data to mess with it so far.

Just and FYI those are my pages and Video, and I also don’t have sliding sync working yet. I work on it here and there, but other than Element X, I’ve had no issues getting clients to connect to my servers running dendrite. I’ll update those docs, and probably do an update video when I get it working on Dendrite.