There is already a couple like this. lemmy.dbzer0.com for example is a piracy themed instance, and all communities hosted on it are piracy-related.

1337x.to has a great totk upload in xci format if you need one. Torrentleech if you have an account there is also fine.

You don’t need to sign up for different instances. You only need one user on one instance, and you can browse, subcscribe, and comment on posts from other instances from your own home instance.

Spoiler: They couldn’t.

Yeah, there needs to be more cohesiveness in between all these random instances of Lemmy.