The place I live in does have a regional accent, but I don't have it. I would say it's a 50/50 split of who does and who doesn't, from the people I know. My father does, my mother doesn't. You'd know I wasn't from Edinburgh, Manchester, Derry, because they are very distinctive. My voice is pretty non descript. Like DM.
Just because you’ve adopted/retained an accent that isn’t dominant in your area doesn’t mean that the accent doesn’t have a regional association. Accents bleed all over the place in a mobile society and shift quite quickly over time (and even within individuals over their lifetimes.)
You have an accent. You might think it’s the ‘proper’ one because that’s what you’ve always been told by people who think that accent as a signifier of class is important, and that’s why RP/SSE do exist as minority accents outside the South East - because a class obsessed society dictated that it was ‘better’ and parents of a certain class (or with aspirations to that class) ensured their children spoke with that accent. I know people of my grandparents’ generation who wouldn’t send their kids to the local village school because ‘heaven knows what sort of an accent they’d develop.’
You’d also never guess where I’m from by my accent as mine is pretty much now the accent of where I live. That would probably make you happy as it’s the one you think is special and neutral. It’s not, it’s an historical quirk that people have been brainwashed to think is somehow ‘neutral’.