I linked my battle net account to my D2 R account, on Xbox Series X. So will the game use my Battle Net name or will it use my gamertag on Xbox?
Sadly it uses your XBox GT. I was personally a bit annoyed by this, as it seems the days of having your Hero’s custom name shown above their head is obviously gone. That was quite important among my original D2 clan, so it looks like another GT change may have to be in the works… 
Oh cool. I want my name to be my gamer tag. I’ve pretty much retired my PC account.