You've gotten some very good and very specific advice. So here's some more - .02$ worth from a more relaxed vantage point: I've been shooting for some years with a Leaf Aptus II back, 33 mp, and very happy with it. It has enough resolution to do whatever is needed, smaller files so that the time to check focus isn't so long, full 100% viewing to check focus (very nice), and the colors/highlights are just lovely. Can't imagine a nicer place to be, although it isn't cutting edge, it works very nicely.
The recommendation I'd offer would be to get a Cambo WRS, a lens, and a back. If you get something like the back above, you can happily shoot with the last generation of lenses (such as the 47, Apo Sironar 55, etc.) and be quite happy. They aren't so expensive, and maybe not 20mm shifters, but pretty much up to 15mm. If you want to go more extreme, the 35XL isn't so beloved anymore by the "bleeding edge" guys, so you can get that for less $$, and with some care, get some shift out of it. But maybe the 43 would be better. With shifting you can make these lenses do all sorts of things, and with a pancake camera, the stitching is rather straightforward.
The Cambo is very good value for the $, a simpler and honest camera. With the movements in 2 directions, you can get enormous real estate out of your lens. Rather than going for "the best" or "the right", try getting into the swimming pool and see how you feel about the water. You could get into this system for your budget.
This way of shooting is a very different experience, more thoughtful and contemplative, and the results are quite different. Hard to assess from a distance. It is only suggested if you are looking for some variant of the view camera experience, but in digital. If you want something faster, or not tripod based, that's a totally different line of thought.