Yeah, this is going to be a massive war between Blackbeard Pirates and Red Haired Pirates. Law was defeated the second Blackbeard landed on that island.
The Blackbeard Pirates are designed to look like the underdogs because that’s how Oda writes fights for characters like Blackbeard. However, you’re deluding yourself if you think Shanks is going to end up the stronger of the two between him and Blackbeard and obsessing over the power levels of it.