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human
[Avengers Endgame]Why didn't they time travel back to Titan or Wakanda?

Lets say they time travel to Titan just before or during the Battle.
Let the Battle play out as normal until Thanos is pinned, then stop quill from getting to Thanos.The Gauntlet is removed and Thor could kill Thanos with Stormbreaker, then just ask for the gauntlet or steal it.They have 4 of the stones and can get mind and time like they did in the film.No sacrifice needed,Gauntlet premade, 2 trips and past Thanos doesn't come to the future.

Or

Time travel to Wakanda just as Thanos kills the Vision.Let Thor stab him with Stormbreaker then have someone grab Thanos's left arm and have future Thor cut it off with Stormbreaker.No sacrifice needed,only 1 trip albeit it would be risky.

Why didn't they do either of these?
gpt
1) They didn’t know about the sacrifice for the soul stone. They knew Thanos killed Gomorrah but not why he did it. So they couldn’t have planned for it. 

2) Like you said, it’s way riskier. If they’d gone to Titan, and Thanos realized he was outnumbered and out matched all he’d have to do is space stone his way out of there and they’d all just be standing around on Titan twiddling their thumbs. Same with Wakanda. One mistake, one miscalculation on what time period they come out at, anything, and Thanos is gone. They don’t get the stones and their one chance to bring everyone back goes along with him.

Going back where they did was much lower risk. They knew the dangers everywhere except Vormir, and knew they could handle them. And even with all the planning they did, a bunch of it fell apart when push came to shove. Loki vanished with the tesseract, and Nebula got captured which let Thanos come to the future. Imagine how much worse it could’ve gone if their whole plan depended on getting the drop on Thanos during some small window of time on Titan or Wakanda.