Any popular distro

Mint.

You're already familiar with it, so it will just be the least time invested doing stuff.

If you're trying to squeeze out performance/efficiency, you can load CachyOS and play with it. As an example, it has a scheduler (lavd) specifically designed to minimize idle power use, and another one (tickless) specifically optimized for docker containers/VMs. It has easy access to optimized Java to make modded Minecraft faster. Stuff like that. But ask yourself if you want to spend time messing with that.

~~I use truenas scale. And then run servers like Plex, ersatz tv, Minecraft, and palworld. ~~

I think I misunderstood. If you're looking to play the disks on a display, truenas won't work for you.

not so much the variant but the tooling you'll use..

ie, ive been usin docker+portainer

my fav setup is kodi, emby, minecraft.. all the arrs' running in containers on mint no problem. i suspect any docker compatible variant would work, but mint is groovy.

Like you've already heard, you're unlikely to feel a difference across most distros. I'll recommend Debian or Ubuntu, I use both