The problem with anime is that they make new communities all the time about the latest thing or so. So you can't really block communities and expect that to make anime disappear. And as others have said, blocking users also doesn't help as they also keep changing.

So what's left? Block entire instances that seem to be mostly anime. That's somewhere in your settings. Or stick to your subscribed feed. You can change the default feed also in your settings.

And to clear up one misconception: Lemmy has no way of measuring your interest in topics and doesn't track what links you click. The "everything" feed is just a combination of what everybody on Lemmy posts.