If you click the small Arrow in the top right of a post, there are usually some options to manage that post. Often, there is "See less of X person", "See less

If you click the small Arrow in the top right of a post, there are usually some options to manage that post. Often, there is "See less of X person", "See less of this kind of post", "Unfolow X person" and other other similar options. I use it all the time and ended up with a feed that doesn't change much (maybe one new post per day, but that contains content I actually care about.