It sounds like you're talking about "channel" subreddits, the ones that just form as arbitrary sets of people gather to—however ephemerally—discuss a topic, without ever really self-identifying as "members" of that place.
I find that the best subreddits are the other kind: real communities with members identifying as "member of community X", not focused on or created "out of" the Reddit community itself, but rather bringing in people from the outside because "the X community" happens to use a subreddit to communicate, rather than using Slack/Discord/Telegram/etc.
In other words, Reddit is IMHO at its best when it's serving as a (shared-infrastructure, shared-registration, shared-administration) host for otherwise-independent forums.
Reddit succeeded at being the thing that e.g. Discourse.org was trying to be—a cloud host for forums—by getting the most attention and virality, by taking advantage of the network effects that come from integrating those forums into one larger meta-forum structure. But that meta-forum, and the random "by Redditors, for Redditors" forums that shoot up out of it, aren't the real value-prop. The individual forums hosted for their own communities' sakes are. The meta-forum is just there so that people are aware that Reddit exists when they're thinking about which cloud forum host to use.
Those independent third-party forums are healthy self-contained communities, because they're planned—they were probably started by a PR effort of a company or nonprofit org, and probably have real, paid "community managers" assigned to moderate them.
Reddit's own random-offshoot forums have none of these advantages. They're just people who wandered into an empty space, sat down, and started talking. Of course they don't have functional moderation. They're cliques!
Next time you're looking at a subreddit, ask yourself: does this subreddit have a website? And could it be said that the website "owns the subreddit" rather than the other way around? If so, then great: it's an independent community that happens to use Reddit to host a forum. If not, maybe don't even bother. (I'd love to see a list of the top subreddits that are left when you apply this filter.)