Not really contradictions, there are those behaviours which you describe (i.e. speeds at the outer regions if galaxies faster than originally expected) and from those we come to things such as dark matter which describe these, but we don’t yet know what they are.

It might be that the theory needs to be changed if there is no such thing as dark matter and it Is jnice calculation trick that actually mean something elsr in the real world, but as of right now it describes most things well.

Alas, there is the disconnect between different theories that don’t work together (see Gravity and Quantum mechanics) or only on different scales

I mean, to be fair that is what the linkes page says, but people are misunderstanding the hypothesis everyone calls many worlds (also what the page says) as Many worlds is just a follow up of the theory not the theory itself.

Like Einsteins Relativity didn’t say in the theory that we would be able to predict Mercury’s orbit, but it comes from it.

You OK?