For your own blog, to find the audience is the only right way, I agree. But when you want to share a Hive post of someone else, you need criteria for choosing one as well as for choosing a subreddit for this share. From time to time, I scroll Hive feeds in search of posts that may be popular on Reddit. When I see a post that seems interesting to me from the point of sharing (even it's a boring post to my taste), I analyze it if it's about a solution or novelty and trying to understand who is interested in such a solution to choose the best subreddit. Posts can be highly entertaining or very beautiful but in 99.99% they aren't enough entertaining and beautiful to make Reddit readers follow an external (Hive) link.
The same thing, if someone wants to write a shareable post, they should think in advance about what use this post can bring and to whom. Until you are a celebrity and everyone wants to see your everyday life and read your random thoughts, you should write posts that help other people.