I prefer docker containers (on proxmox VMs), but that could just be the familiarity of a few years experience talking. It does add some distance from 'bare metal' but it also makes backup/restore, and therefore portability, quite simple. I backup both the VMs and the 'persistent' container data that I always create dedicated volumes for, so I have a couple of different avenues and granularity for restoring.

There's nothing else out there, that I know of, that offers improvements on any kind of scale that it would be worth my migrating to.

I do hear good things about podman, so if I was starting from scratch I'd look into that. I have one podman instance running UnifiOS, but that's only because there's no official docker compose from Ubiquiti (and maybe that's telling in itself). Podman feels more opaque to me than docker, but I have years under docker and essentially zero under podman.

I had an easier time moving a project from docker compose to k3s after wasting so much time with podman compose (maybe expected considering than k3s is still root daemon)