Yes, we need to do something about this and tomhow and I are talking about it - it's not clear yet what. Raising the quality bar would likely cut down on quantity as a side effect, and that would be a nice solution. One idea that a user proposed is a review queue where experienced HN users would help new Show HN submitters craft their posts to be more interesting and fit HN's conventions more.
More seriously though, I think some sort of curation is unavoidable with such topics. If you get inspired by stack overflow where you have some similar mechanics at work, then I'd say that is not too bad. But of course you risk some people being angry about why their amazing vibe coded app is not being shown. Although the more I think of it, this might be a good thing.
Edit: One more thought just came to my mind. A slight modification to the curation rule, you let everything through, just like now. However, the posts are reviewed and those with enough postive review votes get marked in some shape or form, which allows them to be filtered and/or promoted on the show page.