Yea, TrueNAS comes with a jails manager which has nothing to do with NAS. It's incredibly feature rich: https://static.ixsystems.co/uploads/2020/04/image-4.png

Plus the setup now gets intricately coupled with the host OS. That's a big no for me. I want to treat the host OS as disposable, ephemeral and decoupled for peace of mind. The host's only job is to serve files over samba protocol and run scrub cronjobs. That's it. It gets 2 vCPUs and 24GB of ram. Stays put.