If you’re on damus, you can use profile action sheets to quickly unfollow users from your home feed by just tapping on their profile. This will take time but eventually you’ll get rid of them all as you come across them. You can also DM this npub @NostrAIDVM saying hi. It’ll respond with a list of commands. You can get a list of npubs that are inactive and then you can unfollow those as well. That’ll reduce your follow list a lot because many of those npubs won’t come back.