If you want to use ZFS, then TrueNAS with sensible defaults is a great way to go. If you want to learn ZFS enough to roll your own deployment, change the configuration correctly and understand the changes you make then don't start with TrueNAS, and definitely don't listen to the TrueNAS community.
Or at least, that's how I read the GP comment.
I evaluated TrueNAS Scale about 6 months ago and bailed on it very quickly. My install with their "sensible defaults" ended up having swap partitions on all my spinning disks. That alone was enough for me to decide against using it. One bad choice likely means other bad choices in my experience. They also trampled / reset my 'zfs_zrc_max' tunable every time a VM got started (I think) and it wasn't obvious what was doing it.
I didn't think there was any value in learning the quirks of TrueNAS over doing a setup from scratch, so I ended up going with Ubuntu LTS and doing all my own config / testing.
I know, I was doing just that 5+ years ago.
Commercial storage vendors aren't really any different. Mostly the biggest difference here is they offer a very limited subset of hardware and disk configurations and tend to iterate over that very small configuration space. Step outside of that config space and they won't have much insight.
This remind me of the earlier days of Mac vs PC. Mac tended to have a very small hardware set of supported devices, and in many ways helped stability. PC supported pretty much anything you threw at it, which commonly had issues with crappy drivers and untested interactions.