The Resistance to Non-Locality in Quantum Field Theory

Quantum theory and general relativity get proposed roundabout the same time in sense, you know, it's going to run the same period. Both of them are really interesting and deep and have lots of counterintuitive implications. The quantum multiverse is one of them for quantum theory. But while GR, general relativity is largely considered as very hard to understand but still fine. I don't know why we haven't moved past this stage given that there is a perfectly fine explanation for how the quantum multivus works.