I can't speak for @early-whale-57281's experience, but here's my understanding. TrueNAS used to run on FreeBSD. They made the odd choice to allow users to deploy additional services on TrueNAS with Kubernetes -- that's odd because Kubernetes explicitly leverages containerization in Linux, so they had to virtualize a Linux Kubernetes cluster to deploy services. So they basically were using a foreign containerization system to deploy apps. I don't think this is the case anymore, I believe TrueNAS just runs on Linux now. (BSDs are often considered for storage systeme because there's a whole bunch of ZFS licensing issues on Linux -- ZFS is the preferred filesystem for large scale storage usually)