probably cause he is the smartest of them all. Dr. Strange movie, he started as a super weakling but towards end of the show his skills improvement qualify him to be a master in such a short time.

Then during Infinity war, the way how he battle Thanos really blew my mind. The magic that he pulled out was amazing. I wish the fight was longer.

Then End game,did he just open portal from Titan to Earth?? He can't even do it previously but safe to assume during his 14 million tries in defeating Thanos, he has learn a lot of shit from TimeStone