Has anyone used UmbrelOS or CasaOS?

I use Casa"OS". It's fine, but nothing groundbreaking. Cockpit for example can do pretty much the same, and for Docker containers, I nowadays mostly use docker compose.

But hey, it helped me a quite a bit in the beginning, and it's cool. Pretty basic, but enough for most people, mainly beginners.

Check out cosmos cloud too...

I tried umbrel and wasnt super impressed. It seemed like it would function alright for the small amount of things i was trying to do but broke shortly after installing. I set up pihole and i think jellyfin since i was just testing it out on an older laptop.

I've heard decent things about CasaOS but have not used it myself.

I think I had a look at most of them except Umbrel. Bit of a mixed bag for me and none of them struck me as outstanding. On paper I fancied Runtipi but I struggled to get that up and running even with Debian 11. Liked the inbuilt proxy servers but some of the apps I tried fell over so there was that. Some of them seemed a bit of a walled garden, for instance cosmos cloud provides constellation vpn, free for now but intends to charge for it later. Having commited you might find in future that transferring your containers might be difficult because of the way that they are created to work with the specific application. I decided docker and portainer was simpler for me. On a similar journey to create NAS looked at Proxmox,Truenas Scale and OMV. I'm coming to the conclusion that they're nice but I don't need the level of sophistication they provide. The GUI are nice but I could build on Debian or Ubuntu for my needs, mostly containers and the odd VM.

Debian and occasionally rocky and fedora