The decline is not surprising. I am sure AI is replacing Stackoverflow for a lot of people. And my experience with asking questions was pretty bad. I asked a few very specific questions about some deep detail in Windows and every time I got only some smug comments about my stupid question or the question got rejected outright. That while a ton of beginner questions were approved. Definitely not a very inviting club. I found i got better responses on Reddit.
Would you care to link to any of those, even ones that might appear to be deleted?