It would be super helpful if we can hide entire instances from showing up at an individual level. For e.g. I see a lot of posts from feddit.de - I don't have anything bad against the server or the users, but the posts there add no value to my experience and fill up my feed with content I'll simply not understand. It would be a better UX to be able to hide these without having the home instance and other users on it be affected by your preference.
(Looked like someone else told you another way to get the same effect, but this way you can input any you know of without having to wait to see the posts. Maybe?)
If you click on the 3 dots to access the post options for a post from that instance, there is an option to filter out just that community or even that whole instance. I've done that with several non-english instances.