FreeBSD was the reason I chose TrueNAS Core. Unfortunately, you are right, TrueNAS Scale (Linux) is where they are focusing all their attention. At this point I will not purchase additional TrueNAS equipment as I feel I was "rug pulled." I get that they are going after more of the Docker container/app market, but I just want a solid ZFS w/excellent networking NAS device. Linux is close to this ideal, but it isn't as "Set and Forget" as FreeBSD (IMO).

You usually don't really interact with the OS underneath at all so I don't think it makes much of a difference unless you are very fond of Jails.

I mean that is the whole point of a NAS OS. It gives you a GUI and you don't have to worry about the rest.