We are also told by CDPR that they won't "withhold story content for DLC", which would exactly be the case if we got such DLC.
Also, not many players got to the Nomad ending, which was optional, making it even less likely to be canon. Do you really think they are going to discard all the work they did in NC so they can build a DLC based around the Arizona desert?
That is without even considering the fact that there are 3 paths in the game, and it would absolutely make no sense for them to force all players to go into a Nomad storyline.
I also think an Arizona-Map is very, very unlikely.
A scenario I could imagine for a post-ending DLC that kinda lets all decisions continue is like a short intro-part similar to our origins, depending on the ending you rolled with - and then converge into the main story of the DLC again, also like the main game did.
So for example V returns to Earth/Night City from Arasaka prison because they want her to do a job, promise something in return.
V returns from Arizona after a short stay there, with a hint her situation could be salvaged in Night City after all.
And Johnny-V tells us in cyber-space or whatever that he stays true to his words and gives you your body back, because for technobabble reasons it is possible after all, he only wanted/needed to do something for that ... but you still need to go back to NC to salvage the six months nonsense...
Something like that. In a way, that ALL endings seem to be somewhat similar as with V having not long to live makes such a DLC a lot easier...which gives me hope it was always the plan...but I really do not like the idea of having these hopes and then getting them crushed with a
"Look, our only DLC will be the story of young Jackie Wells - you people loved Jackie, now play as him, right until the moment he dies! V...who?" urgh...