On Titan, Doctor Strange could've easily knocked out Star Lord before he went berserk on Thanos, as he had already foreseen different outcomes of the upcoming battle. But, he didn't. I think that the main reason for Doctor Strange to consider the outcome of Endgame to be the only 'true victory' was that the Infinity Stones needed to be completely destroyed, and if they stopped Thanos, then none of the Avengers (especially Doctor Strange himself) would allow the stones to be destroyed. The universe is a big place. There must have been hundreds of powerful beings scattered all around the universe seeking true power. But, I don't think that the trick of 'using the six Infinity Stones at once' to grant wishes was well known to everyone, until Thanos discovered the secret. If Thanos would've been killed on Titan, then the Avengers would've scattered the Infinity Stones all across the universe again. But, who's to stop another power-hungry villain from gathering the stones again? There's no telling how far the next villain would go to get his wishes granted. You see, Thanos was on a mission, which was quite noble in his eyes. He didn't want to kill people himself. He wanted to leave the fates of the people across the universe to chance. That's why he didn't want to kill the Avengers & the Guardians on Titan. His only mission there was to get the Time Stone and go back to get the Mind Stone. But, what if the next villain simply kills all the heroes coming in his way and then does something even worse than snapping away 50% of the living things? I think that Doctor Strange saw this outcome in one of the 14,000,605 alternate futures. Fearing the next threat to be even crueler than Thanos, Doctor Strange decided that there was no other way to truly win. The Infinity Stones had to be reduced to atoms. What are your thoughts? On a side note, Agents of S.H.I.E.L.D. Seasons 6-7 and Runaways Season 3 could take place in an alternate timeline where Thanos was beaten on Titan and the snap never happened. As to what the agents were doing in the Main Timeline, I like to believe that their story was over after Season 5 (just as the writers initially intended it to be). About the Runaways and Cloak & Dagger, they probably defeated the Magistrates in the Main Timeline without the time jumps and the time travel shenanigans.