> After a while, I stopped having to post questions about "common frameworks", either because I could do with the official docs of because there was already a StackOverflow answer for my question.
Good. That's the site working as designed and intended.
> What was becoming more common was that I would have a question similar to an existing unanswered one.
Then you should improve the existing unanswered question instead, and/or draw attention to it (https://meta.stackoverflow.com/questions/265874 ; https://meta.stackoverflow.com/questions/266338). Or, yes, answer it if you can. Thank you for doing so.
> Or that my question would never receive an answer (presumably because my questions were becoming more tricky/niche).
That's a big presumption. I got an answer to https://stackoverflow.com/questions/75677825/ within hours.
> for some reason, a few years ago my questions started being closed for no apparent reason other than "those who reviewed it have no clue and think that it is invalid"
This is absolutely not what happened. First off, when your question is closed, you get a banner at the top of your question indicating which of the few standard close reasons was chosen. The wording isn't always a great fit (especially in the cases where people voted for more than one close reason - please keep in mind that we neither write this explanation nor get to choose the text; it's pulled from a database following simple mapping rules, and even moderators have only very indirect influence over that database) but it does normally point you in the right direction.
Second, "I don't know the answer" is not a valid close reason. People constantly accuse (on the meta site and elsewhere) that someone else's close vote was motivated by this; there's never any real way to evidence that, and this kind of accusation is in fact what we consider toxic behaviour (an assumption of bad faith).
> Many times they closed even though I had posted both the question and the answer at the same time (as a way to help others)!
The fact that you provide your own answer weighs exactly zero in the calculation of closing a question. It must meet the site standards. Part of the purpose of a question is to index the information in the answer - so no matter how brilliant your explanation of the underlying problem might be, your exposition of the problem is a limiting factor.
> The first few times, I fought to get my question reopened and guess what? They all got a few tens of votes in the following year.
The community does make mistakes, in both directions. The meta site exists for a reason.
But part of "fighting to get a question reopened" is editing it. Changes you might think are trivial might be crucial according to our standards. Some questions fundamentally can't be fixed; but when they can, closing a question signals that the OP's perspective is needed to fix the problem, no matter how minor. If we could fix it (without worrying about trampling on your authorial intent), we would.
>Still, that toxic moderation hasn't changed. If anything, it has gotten worse.
It's not moderation, but curation. It's overwhelmingly done by a community of volunteers - not by the two dozen or so moderators (also volunteers) looking over an accumulation of literally millions of users and questions.
And it isn't "toxic". Overwhelmingly, people aren't doing it out of any kind of vendetta or a desire to cause you or anyone else a problem. They're doing it to uphold a standard (https://meta.stackoverflow.com/questions/417476/) designed (really, developed over many years by community discussion on the meta site) to accomplish particular goals (https://stackoverflow.com/tour ; https://meta.stackoverflow.com/questions/254770).
> I am usually better off opening an issue or discussion directly with the upstream project
If it's something that makes sense to handle this way, it probably doesn't also make sense in the Q&A format. We can't do anything about your bug report.
> I heard people mentioning that LLMs were hurting StackOverflow badly.
A lot of people think so because the volume of questions has dropped off dramatically, and there's good evidence that people will ask an LLM instead of asking on Stack Overflow.
But this is not at all "hurting Stack Overflow", unless you're a staff member at the company and you specifically worry about the effect of this decline on ad revenue.
If asking an LLM - trained on millions of existing Stack Overflow questions, along with the rest of the Internet - gives you an actually working answer (and you're either in a position where you can deal with AI hallucinations, or are lucky enough not to experience one), then that is, almost certainly, not a question that helps improve the existing resource that is Stack Overflow. It's most likely a duplicate or near-duplicate.
Duplicate questions on Stack Overflow are not inherently bad; sometimes rephrasing a question helps by providing a "signpost" so that people who think about a problem in a different way can realize that it's still the same problem, and there's still the same fundamental question to answer about it. But we want everyone who has that question to find the same collection of answers; and we want that collection of answers to be high quality, not redundant, and categorized under a high quality version of the question. That way, when you use a search engine and find Stack Overflow Q&A, you get the best possible result, as quickly as possible.
Nowadays, there are about three times as many publicly available questions on Stack Overflow as there are articles on Wikipedia. Considering that the scope of Stack Overflow is "practical questions about programming", while the scope of Wikipedia is "literally any noteworthy real-world object or phenomenon", that's clearly too many already. So why worry about the influx of new questions slowing down?