The Many Worlds Interpretation doesn't even make sense as we cannot see wave functions, they don't even exist in spacetime but in an abstract Hilbert space. If you say the whole universe is made of invisible waves, then how do you explain everything we actually observe? The interpretation has no local beables, nothing you can actually tie back to observable reality. It is incoherent.

The double slit experiment is just due to the principle of complementarity. It's not more complicated than that. It doesn't need a "resolution." You are inventing a "problem" to solve.