Same for me. What I do is subscribe to communities I am interested in and show only subscribed feed. Then federation came and I wanted to be able to see other posts too, so I just abuse the communities blocking feature to block everything I am not interested in while having all as my default main page filter. After a while, I was able to block most of the unwanted communities and now I have mostly interesting posts in my all feed.

What really helped me is to use Jerboa on Android to quickly block communities straight from the posts (that is something I would probably welcome in web app, too). It is much quicker than having to go to the profile settings.