If you subscribe to some communities, you WILL have an option to see posts only from those communities, you shouldn’t have to go into a community unless you only want to see posts from that particular one. Also, I’m new but the default sort is usually “active”, which I assume means posts which have a lot of activity, such as comments. Try setting it to hot or something else to check whether you get a better variety of posts.
If you subscribe to some communities, you WILL have an option to see posts only from those communities, you shouldn’t have to go into a community unless you only want to see posts from that particular one. Also, I’m new but the default sort is usually “active”, which I assume means posts which have a lot of activity, such as comments. Try setting it to hot or something else to check whether you get a better variety of posts.