I find that in recent years my best resources are official docs because that's where I find the "obvious" answers to the issue I'm having by not having previously read the docs. I also find lots of answers in gh issues (often unresolved) where I gain insight into what might be happening so I can come up with a solution. SO answers that I find useful are usually ones which link to related docs.
Why is that in recent years. The best resources have always been thofficial docs and that has not changed since before SO. The issue is that official docs are often not good and you need pointers too them.
In fact I would say that official docs are getting worse and you need more help from SO now.
Agreed that github issues are very useful for understanding. But even there for popular reps there are too many stupid questions to wade through.