Okay just for everyone's record, I have a 2021 DD40 228206 and this categorically has underside AR. Sorry I tried to get a photo of the etch but i'm finding it impossible to do.
I found a picture showing the lazer etched crown in the crystal that shows if it as AR or not and this one has the 2nd circle in the crown unlike my daytona. Curiously, my Daytona is a very early 2019 model and doesn't have AR though the link above suggest it should have.
https://nobswatchmaker.com/blog/how-...ective-coating