IIRC, the biggest issue with TrueNAS SCALE + Docker is that they really run the containers on a ‘hidden’ kubernetes cluster and obfuscate the standard docker and docker-compose way of doing things behind a gui with limited customization and poor field descriptions.
I found it much easier to spin up a VM on SCALE and run docker through that, although then you have to deal with multilayer networking.
… To be fair, this was when SCALE was still in beta, so it has possibly improved since then.
https://www.zimaboard.com/
recent blog from hacker news
I can’t personally attest to the “easy to use self hosting OS” since I immediately installed Ubuntu (soon to be Debian) but the hardware is good and the preinstalled OS should let you get a feel for things.