I thought even if Kenobi ‘did’ refer to him as Anakin, what if copying and pasting Vader’s line from RotJ about ‘that name no longer having any meaning to me’ as a response to Obi-Wan maybe could fuel his anger even more while also adding more dialogue to the duel?
Then there’s also the second time Ben calls him Darth. It’s not like Vader will go into a fit of rage like his grandson… 😂