I haven't seen any responses on Private Compute, which is a client-side framework to do "work" that is too expensive to send to a google cloud service and back. Most common use is live captioning from audio with no caption stream.
Private Compute is heavily criticized by those who value freedom of software on Android because it is clearly doing other things, simply based on CPU use and activity, but the application is more or less a "black box", we the public don't know how it works.
Install on 512mb, remove and trim system services, and lower the memory. Running KVM is by itself likely not going to let you do that, I suspect.
Use Alpine as you say.I run many alpine containers on between 25MB and 60MB, I give them 256MB, but it's way overkill.
Regarding alpine, be prepared to find differences from glibc and systemd distros in places you don't expect. PHP (god forbid you should need it) is a right mess on alpine. Mongodb will not work on alpine. Stuff like that.
I may take some challenge on this, but the tcpip stack seems faster on alpine than in debian, at least in my use cases.
Proxmox has a lot of tools I don't need and I didn't like how proxmox manages storage. Now I use Incus, mostly because incus doesn't care about your storage back-end, networking, etc.
I used to use Plex and now use jellyfin, not so much because one has features the other doesn't, but because XBMC became what they said they never would be. That's going back a ways, but I just saw the writing on the wall a few years ago that Plex had stopped caring about free users, and I was an admittedly free user.
People focus on monetary cost, but there is a price to Jellyfin, which is that you're on your own with all the plumbing. I'm OK with that, but I can see why someone wouldn't want to faf about with it.
Jellyfin will one day become what Plex is now, that's the cycle of things.
Most cameras do not do the heavy lifting of face/person detection on hardware, they send the streams to some cloud for processing. Just be aware of that.
Easynews and nzbgeek.
Well worth the 30euro each per year.