Thanos has a Power Stone stuck to his right hand and an IG with the Power Stone on his left hand. He gets 5 seconds prep, armor, and his sword is lying 10 feet away. Thanos becomes bloodlusted whenever he grabs his sword, which will be when he realizes that DD is tougher than he originally thought. No prior knowledge.
Battle takes place on Titan, 1000 feet apart. DD starts out base but when he absorbs enough energy equal to whatever he absorbed from the nuke + the re-entry fall, he will adapt.