If you use docker heavily, *bsds are not an option. You do not need a *bsd just for ZFS, although it is supported quite nicely. I use zfs with proxmox for my server, which is debian based.

I would recommend using debian buster. People lose their minds over systemd and it's ridiculous. Debian has been the best experience of any distro that I've used, and I've tried most of them. For my router I use openbsd.