If you truly want to see “everything”, it’s best to join a small instance that is federated with everybody. I joined an instance called Rammy. It’s nothing special in and of itself, just one guy nice enough to host the server. But I can interact with Beehaw, Lemmy.ml, Lemmy.world, Lemmy NSFW, all of it. So if that’s what you want, join a small instance.
If you truly want to see “everything”, it’s best to join a small instance that is federated with everybody. I joined an instance called Rammy. It’s nothing special in and of itself, just one guy nice enough to host the server. But I can interact with Beehaw, Lemmy.ml, Lemmy.world, Lemmy NSFW, all of it. So if that’s what you want, join a small instance.