I mostly use debian + docker or alpine + docker for this kind of thing (usually running as VMs on a proxmox server). Both are utterly reliable in my experience, though I’ve been tending more often toward alpine these days, because it’s just so light and simple. I haven’t tried any of the immutable systems, in the general spirit of why fix what’s not broken. I don’t even bother with snapshotting either, though that’s mostly because I use some of the proxmox tools for backing up the VMs.