It seems to me that the best solution here is simply a daily thread limit. The issue is not really low effort questions. I mean, that is an issue on some level, but we typically respond by asking for effort and don't moderate over just that. At any rate, the issue would be present even if all of the questions were high effort. The issue is an excessive number of threads, regardless of their individual quality. Solving this doesn't seem to require human judgment on a case-by-case basis as individual thread moderation does, merely the selection of an arbitrary daily cutoff, maybe 5 questions per day or 10 questions per day and no more than 2 per subject or something like that, and an automatic cooldown timer. Then no one has to guess about how much is too much, no one has to get punished because the system just prevents additional threads, if someone really has to ask more than X questions in a day for some unfathomable reason they could create another account (even if someone created many accounts to ask high quality questions, the forum would just look active and not what it looks like now), etc.
I am aware that none of this can be done without admins, just theorizing.