here, let me show you how much of a retard you are
>If the Avengers were able to detect Thanos' use of the stones on his planet, why did they have to wait for Captain Cunt to arrive with Nebula?
they discovered where thanos was after tony and nebula came to earth, it's explained in the movie by rocket.
>How did Iron Man solve time travel without ever having previously established knowledge of Pym Particles
>If he was able to solve it without knowing about it, why didn't it ever occur to him earlier?
he wasn't looking into the pym particles, he was looking for what one could do in the quantum realm retard. It's also seen that was his first attempt with the quantum theory and scott lang already gave away multiple ideas before tony found out time travel.
>How did Banner have enough control over the Hulk to merge with him when it had been previously established that Banner had zero control or even awareness when the Hulk was out
Bruce literally tells in the movie how he could do that fucking retard. Are you that retarded that you need someone to explain it a million times before you get it?
>If Tony and Steve went to the 40s to get the tesseract, how did they ever have the ability to lose it to Loki in NY, causing them to go back further?
>the Grand Wizard tells Banner that if he takes the time stone into "his timeline" that hers will be fucked up, clearly showing that they didn't time travel, but instead went to a separate universe, contradicting the very way the time machine works
Because they go back and return them in that time frame and place later. They say that in the movie, are you fucking dumb.
>Why did Thanos go from "misguided dude with a purpose" to "murderous CGI monster who loves being evil"
Because he found out that he would finally fulfill destiny and erase half of all life. He then realises that even when he does that, people will not accept their fate and that pisses him the fuck off.