As for the docs…
No, they are. All the other resources are shortcuts to get a proof-of-concept out there more quickly (or to get one common case implemented quickly). Actually the best-written software bring you to PoC stage from the get-go. E.g. for OpenSSH, just install the package and start the server. Now it works and you can peruse the rest of the doc to do what you want.
if I wanna setup an authoritative DNS server, I need to find how I set one up
Yes, so you read the doc. That’s a pretty unfortunate choice for an example because bind has excellent doc, walking you through an introduction to DNS and Bind itself, then what machine you need to run it and then how to get your PoC. The rest of the doc is all about how to wield it correctly, as you said.
I am aware that some software does not document nearly all of that but the vast majority brings you to PoC state without trouble before you can tune things, perusing the rest of the doc.
Yes and no. Either you have the experience/knowledge to know what you need (e.g. “I need an authoritative DNS server to solve problem X”), in which case it all comes down to “what are my options?”, which any search engine will gladly answer (and the doc will detail without ambiguity whether or not it’s a good fit). Or you don’t, in which case you either need to build that knowledge or you walk away.
Blogs and articles get stale very very quickly and very often, they are not written by competent people. In the grand days of “host your own mail server”, this very thing has led to so many open relays that ISPs and server providers started to block SMTP by default, with convoluted steps to unlock it.
Yes. It’s just like a mechanics does not like to read literature explaining for a 1000th time how an engine works or a surgeon who loathes having to go through an anatomy lesson every time they try to read content. If you don’t know what you are doing, learn about it first. Often, a wikipedia article and a couple more random reads go a long way towards understanding these kinds of things.
Also with time, your area of soft expertise expends. I have never had to configure bind as an authoritative DNS, yet I know what DNS is, roughly how it works and how to navigate to the right places to get the specific info I need quickly. That’s what experience brings.
Why do you think people have do different trades and learn about these kind of things at Uni level? That’s the point of any degree or education system actually: you build an understanding, lesson after lesson, year after year, just to be able to understand/manage what you are going to be taught next.
If you/I need to perform heart surgery tomorrow, your/my patient will undoubtedly die. Or phrased differently, it gives people who are completely clueless at heart surgery, like me, more and more homework in a snowball that becomes quickly unmanageable. That’s how knowledge works. And as I’ve been repeating (again, without offense), you either learn about it, step by step, or you do something else.
These things are not easy and getting competent/skilled at them requires work.
I might be very wrong about what I am going to say, and again, this is not a slight, I don’t mean to offend anyone, but it looks like, so far, you were able to find articles and blog posts about most of the stuff you wanted to achieve. So you’ve been mostly following tutorials. It’s rewarding: you get things working. But the problem with said resources (besides going stale quickly or not being competently done) is that they are made, originally (before it’s copied 100s of times by copycats), by people who took the time understanding how things work and do the hard work for you. Now that you want more bespoke or niche things, you seem baffled that no one had written a convenient tutorial for you, even to get yourself started. But the “tutorial world” is an illusion. The best way of doing self-hosting with minimal amount of frustration is by getting up to speed with all that background knowledge first or as you go, this is how you go beyond “tutorials”. I am aware this is not how you phrased it but tutorials are the only way “clueless” people get something working. Most things out there are not written for clueless: they assume a minimum amount of knowledge.
Finally I want to reiterate that I am not judging you. I stand by what I said: it is hard and not everyone want to spend time getting experts at those things. It’s fine. Conversely, if you really want to and stick with it, I am certain you can achieve that level of expertise and, in a couple years, maybe, look at that post again and think “I really got upset over little there but it’s true it looked insurmountable back then, good that I stuck with it”. :)