No.
But if you have to explain something, it's best that someone understand in the first paragraph what's on the table.
Use the middle to clearly explain the relevant facts.
Be sure to ask a clear question (what you are looking for/ trying to do/ etc.?).
Sometimes posts don't even contain any question!
I'm not going to fall out with you over this but I will, in a civil manner, disagree with some points you have made. That's what polite discussion is. If we all agreed on everything, there would be nothing to discuss.
You assert that the first paragraph is a thesis setting out the problem.
What's on the table might not be about a problem. It could simply relate to an experience - technical, amusing, unexpected, irksome.....or almost anything.
The middle might explain what you
felt about the experience rather than known facts.
And there might be no questions to be asked.
All I'm trying to say is that there is no prescriptive framework that uniquely defines what is good writing.
There is no one size fits all.
But this is moving off topic which is how posts are presented here.
I have mentioned a couple of times in the past to others that huge blocks of text in a single paragraph make posts difficult to read - discouraging to read. Others here obviously feel the same way.
I post here and on other forums and I see things that have spelling and grammatical errors. I rarely comment on them. The internet is a wonderful invention that allows people to communicate freely across different time zones and on an almost infinite variety of topics. My view is that, if the point being made can be understood, the quality of the language is not that important.
Making it easy to read, much more so. And breaking it up into bite sized paragraphs is a big part of that.