I was planning to install Proxmox for my homelab but didn’t like that it was a whole distro, which shipped with an ancient kernel…
My issue with Proxmox isn’t that it ships with an old kernel is the state of that kernel, it is so mangled and twisted that they shouldn’t even be calling it a Linux kernel. Also their management daemons and other internal shenanigans will delay your boot and crash your systems under certain circunstances.
For LXD you’ve a couple of options:
Debian 12 with LXD/LXC provided from their repositories;
Debian 12 with LXD/LCX provided from snap;
Ubuntu with snap.
In the first case you’ll get a very clean system with a very stable LXD 5.0.2 LTS, it works really well however it doesn’t provide a WebUI. If you go with a the Snap options you’ll get LXD-UI after version 5.14.
Personally I was running LXD from snap since Debian 10, and moved to LXD repository under Debian 12 because I don’t care about the WebUI and I care about having clean systems… but I can see how some people, particularly those coming from Proxmox, would like the UI.
Side note: it should be possible to run the WebUI without snap and use it to control a LXD 5.0.2 LTS cluster but as I don’t need it I never spent time on it. :)