I think of a gravel bike as somewhere between a road and hardtail mountain bike. I have a hardtail and live across the street from a huge network of single track trail, so if I want to ride single track I don’t even consider a gravel bike. This makes the choice of gravel bike easy. Pick the one with features and geometry closest to the road bike. The other decision point would be if you planned on doing a couple of cyclecross races.
Honestly, if your first choice of tires and wheels is 303s road-biased tires I would be looking at an Exploro. You seem to be leaning towards a road bike with tire and wheel capacity to handle reasonably clean dirt roads. Heck, I would almost look at something like a SuperSix, Madone or Domanie for that application. It isn’t unusual to see some of the smoother gravel races being won on road bikes with a 33-36mm file tread tire, like Steam Boat gravel and some of the BWR races.