I believe you’re speaking about General Relativity, Quantum Mechanics refers to “quantum” aka discrete, non-smooth things like the energy levels of electrons.

General Relativity indicates that the temporal ordering of events may appear different to different observers, although there is a way to objectively switch between perspectives.

In all cases, the theories point to a uniform, self consistant reality, as that is in fact their very purpose. If they didn’t work as expected, your GPS wouldn’t be a thing.