Alpine is another distro that packages LXD. I have Arch on my workstation, but I'm not confident about securing Arch on a server. Alpine, on the other hand, is very much suited to be an LXD host. It's tiny, runs entirely from RAM and can tolerate disk access failures. Modifications to host filesystem won't persist after reboot, unless the admin 'commits' them. The modifications can be reviewed before a commit - so it's easy to notice any malicious modifications. I also heard a rumor that they are integrating ostree.

The only gripe I have with Alpine is its installation experience. Like Arch, Alpine has a DIY type installation (but a completely different style). But unlike Arch, it isn't easy to properly install Alpine without a lot of trial and error. Alpine documentation felt like it neglects a lot of important edge cases that trip you up during installation. Arch wiki is excellent on that aspect - they are likely to cover every misstep or unexpected problem you may encounter during installation.

I did not know there were so few distros packaging LXD [0]. It does not come as a surprise that Canonical would not endorse non-snapded LXD though. And it is sad.

[0] https://repology.org/project/lxd/versions

openSUSE packages lxd