I get the distinct impression that HN, like Slashdot before it, has aged along w/ its original audience. I suspect most of the readers and submitters are aged mid-30's to late 40's. Which online communities attract the young weirdos these days?
Reddit, Discord. With the caveat most communities are a cacophony of people not having anything intelligent to say, but there are gems in between. Many educational YouTubers and open source projects have their own community on one or both on them.
I just took a glance at it and it seems substantially better than it was 2 years ago, in both content and design. Back then, it was full of bullshit articles and the site felt like it was made in Comic Sans.