Not to mention the myriad actors using a US accent(s). FWIW, I can't recall a movie/series that, when based in a region the actors know personally didn't do the local accent wonderfully. But, that's the rub: it's such an enormous, overpopulated populated landmass that it's bound to have innumerable dialects.
Although, perhaps what OP's asking is which, if any, is/are considered the common/baseline dialect of US English? 🤷🏼♂️