If I want to make big big prints with a digital camera that is not super expensive, am I best off with a used D800?

I've asked this question before and I always get stupid snarky responses of learn 2 shoot (when I was talking about my 24mp cam)

When I mean big prints, I mean prints that are tack sharp when your eye is 2 inches from the paper

I've yet to see a digital print that is blown up to something like a 20x30 that looks nice with a camera in the 20ish megapixel range, you can see the pixels n shit

is there any options for people that liked shooting large format in the digital realm yet?

I don't suppose there are any cameras out there that are super simple but take extremely detailed pictures right...(like a 4x5 or 8x10 equivalent)?