Time travel is always confusing because there are no specific rules we can apply when analyzing it, it doesn't mean that it was badly written, the whole aspect of them not changing their timeline but instead creating parallel realities made sense. Sometimes you need to watch a movie that has time travel twice to fully get it.

That wasn't the 2018 Thanos. They said several times in the movie that you can't change the future by changing the past. The Ancient One and Banner explained the aspect of creating alternative timelines in the roof scene.

They went to 2014 of THEIR past and Thanos followed them to 2023. What Thanos exactly from what "timeline" did the original stones snap? Saying "you cant change the future by altering the past" doesn't make it true, also if it did... then why return the stones? if they were taken from the past and it doesn't change the future... why put them back at all? I'm sorry the time travel in this film is a complete mess. I still don't buy "alternate timelines" as an explanation.

You know the writers disagreeing with the Russos about the alternate reality/timeline reminds me of the Marvel&Sony Venom thing. Russos: Cap is in an alternate reality/timeline. Writers: Cap isn't in an alternate reality/timeline.

They needed the stones to undo the snap and bring everybody back but by taking the stones they created branch realities. They had to return the stones in order to maintain the flow of time and have a singular reality.

Within the world of the MCU this version of how time travel works makes sense. It's also why Nebula could kill herself without vanishing.

What reality did they go to then when they returned to 2023? It just doesn't make sense that the stones have to be returned but not the individuals. I completely agree the stones need to go back to maintain the balance but if that is the case so do the individuals who set in motion the whole wiping in the first place. Also was it not noted that if the stones do go back to their reality that any alternate timeline gets eliminated? The 2014 Thanos being from an "alternate reality" and dying in 2023 doesn't make sense to me. He was taken from the normal 2014 reality.

It's an alternative reality. The movie was really straight forward about how it's approaching time travel. They literally said that it's not like back to the future, where changes in the past affected the future. It's also why the Gamora we knew up until Infinity War is still dead.

I get Gamora is still dead. But saying "changing the past doesn't effect the future" doesn't really fly with me, that's not giving an explanation as to WHY.

So basically you're saying they went to their past took the stones and went to an alternate future timeline that had the same Thanos issue, 2014 Thanons came with them afterwards from their past then was killed in that alternate reality. So where... are the Avengers of that alternate reality if it's alternate? shouldn't there be double? Or did all the event's happen the same in that reality and the avengers don't come back from that reality? I'm just not getting it. ALL time travel literature I can think of follows the same idea behind how it would work, go to the past, fix the issue, the future changed #done. You either can't go back and kill your own grandfather as it would make it so you can't exist to go back and kill him in the first place or you can kill your own grandfather just the version of you is out of the timeline forever when you went back in time, when you return to the future you don't exist.

I'm just glad CA returned the stones and then went to a period in time where he could be with Agent Carter. This is an alternate reality b/c there were two versions of CA....one version was frozen deep in the ice somewhere.

They return to their presence, it's not an alternative future. They created several branch realities, it would make no sense for them to be in the same reality if they didn't go back to their presence.

Time travel hasn't been proven to be possible yet and we don't know what exactly would happen if it was. The grandfather paradox is not the only time travel theory, there are tons of works about the quantum mechanics of time travel. In Endgame they are using the Quantum Realm to travel through time and space.

So The Ancient One says that if you remove a stone, then you create an alternate timeline separate from the main timeline. Bruce says when you return the stone to just before it was taken, it erases the alternate timeline. So if Steve returns all the stones and it goes back to the main timeline, then how does he create an alternate timeline when he decides to stay? Does he just keep stealing stones/time hopping with stolen Pym Particles until he gets old?