Tony Stark is Alive
Avengers: Endgame Didn't Happen
I had occasion to rewatch Avengers: Infinity War recently, and something caught my eye. In order to obtain the Mind Stone from Vision, Thanos uses the Time Stone to wind back time, but only certain parts of the timeline are reset (for example, the Scarlet Witch is still thrown to the ground, and Thanos has not moved back to his location before the Mind Stone was destroyed).
From this, I think we have to conclude that Thanos is now in a parallel timeline where the Mind Stone has not been destroyed. This means that in the main timeline — which Endgame taught us is the only timeline that matters — the Mind Stone remained destroyed. Therefore, Thanos never obtained all the stones in the main timeline, The Snap never happened, and, finally, all of Endgame is moot. Tony Stark is alive!
Postscript: Yes, I cried during Endgame. So what?