I said before that one thing I really hate about current social media platforms, including fedi, is that if you subscribe to someone, you get the entire range of topics.
Filters are useless most of the time because it's easy for posts to slip through and other posts to get blocked incorrectly, even if you define hundreds of fine-grained rules. They require too much effort to work at least semi-correctly.

So my idea is that profiles should have a list of channels and when you post something, you have to specify to which channel your post belongs.
When people follow a user, they can configure which channels they're interested in and will only receive posts from those.

Of course, that would require people to go along with this idea and not just create an "Anything" channel.