Which is ironic since huge companies like netflix, sony, citrix, netapp and others make appliances based on FreeBSD and contribute a ton of code (Note, i am not at all disagreeing with your statement, i just find it ironic).
IX Systems does push behind it a lot and does advertise it: https://www.ixsystems.com
I have heard people complain because the handbook needs updating in some areas, but to be fair it is an open source handbook and people can make submissions to help make it better.
My point was simply aiming to underline that there is no analogue of RHEL or Centos in the BSD world. If you decide to endorse BSD you know you are on your own and you have to contribute to the project. The BSD license seems a bit more appealing to this huge giants than the GNU one. Fixing bugs and contributing to the code base is the reason why I love the project.
For purely educational reasons you can learn more in 5 minutes using BSD, than in 10 years with Ubuntu (what is it that one learns with Ubuntu actually?).
The handbook is just awesome. If people complain about it, it is just because they never looked at how documentation is written in the average in computer science (is software documented at all?).
https://www.freebsd.org/doc/handbook/
This is the first and only resource you have to hit when the question is: "how do I do that in FreeBSD?"
Section 4. answers your second question.
There is no less information about BSD than "Linux", it is simply that BSD has no advertisement or companies behind pushing it...