Neither are good enough as a starter. With what we expect of how ETH will have us playing, Dalot as a squad player will more likely be able to slot in without changing our entire style better than AWB would.
AWB and its not even close, anyone who puts dalot has no idea about football, people have this perception dalot is an attacking fullback.. and although he seems more active in the attacking 1/3 his deliveries are horrific. Defensively AWB is one of the best rb's in the league its just a shame he doesn't have it in his locker to contribute offensively
Dalot isn't an attacking fullback. What he is much better at is his build-up play out of the back, helping control the ball and develop possession play. He's not particularly good at it or anything, but he is much better than AWB.
It's also debatable whether AWB is one of the best defensively. He's an incredible 1v1 defender, but he's not that good positionally, fairly lazy at getting back once the opposition get in behind him, often breaks our offside line, and terrible at dealing with crosses coming in from the opposite side. Opposition teams have noticeably started changing how they attack down his side so that they reduce how often they attempt to take him on 1v1 and instead look to play quick passes around him, which avoids his strengths and targets his weaknesses.
AWB actually has a better final ball into the box than Dalot. It's just that he doesn't get in position to show it enough, and he doesn't provide enough in the build-up.