Once you amass a collection of communities that do interest you, you could browse your subscribed feed instead of all. That's what I've done. It got annoying needing to skip past a lot of content that wasn't relevant to me, was crossposted and showed up as duplicates, or was in a language I don't speak. Then you have a whitelist you can grow when you feel like it instead of a blacklist that needs to be added to when new communities show up. Subbing to one of those new community promotion places lets you see most of the active new communities anyway, and you can check out any interesting ones without them invading your feed first.