I’m from North Florida aka the heart of Dixie. I’ve lived in Georgia, Arkansas and North Carolina. Yes, there are some differences - for example Tidewater Virginia sounds different from Appalachian which is different from Cajun and all of those are a bit different from what I’d simply call a standard Southern accent. That said......differences between Georgia and South Carolina or Alabama and Mississippi? Not really.
Similar deal in the Midwest. I can hear rural Minnesota and maybe slightly Wisconsin. But Iowa from Illinois or Ohio from Indiana? Not really.
I can tell a difference between GA, Mississippi and Louisiana from Tennessee but it’s slight. It’s more of a difference in how they pronounce certain words but I can take it further than that. I can tell a difference between the majority of Tennessee and the deepest part of the mountains of TN, as in moonshine country.
Don’t even get me talking about Southern ghetto. LOL That is like a foreign language.