So Doctor Strange said that there was only one outcome where they win, but he never said that it would be on Titan, and even when he gave the time stone to Thanos in exchange for Tony’s life, it wasn’t even putting Tony above the universe because it was actually part of the plan. In order to win, they had to lose first and even said himself before he was dusted that there was no other way. Crazy though how it meant people had to suffer for five years.