When are you going? If you are going later in the year or next year, Galaxy's Edge may be open at DHS, you'll need more than 2 days there probably. Plus I think at some point this year the Mickey and Minnie ride is opening at DHS too.
That's a tough call. Will you have hoppers? Then you can split some days.
Otherwise...I would say DHS unless Galaxy's Edge is open. Animal Kingdom is our favorite, so definitely 2 days there. MK - probably will take 2 days to get through everything.
That leaves Epcot, which I can't imagine going only one day, but I suppose you can - do Future World first then spend rest of day/night at World Showcase, eating as much as you can!