I don't want to make R1/R2 too short because it would make it seem like OP's question isn't worth answering. But Lithiumantis made a great write up so I'll skip it.
I do want to add that everybody, including mad-eyed moody would know to GET CAPTAIN MARVEL BACK ON EARTH ASAP OMFG and it might be just enough time to make a difference. Also Strange would know not to go to Titan. Presumably the only reason he needed to surrender the time stone was that they had no other way to get to earth since they can't turn back time or teleport there.
R3 is the most interesting one because I am not sure if Thanos himself would do anything differently. He just watched a future where he was basically successful in his ultimately plan (having to kill Gamora though, because even knowing where the soul stone is, he knows he can't just go by himself) he might not bother prepping any differently.
His minions however, would do things differently. I am surprised, for example, that Ebony Maw didn't have a space suit. In their universe, something like that would be the size of a button and wouldn't get in the way of his clothes. An Ebony Maw that couldn't be defeated would completely change the events of the Wakanda fight. He'd know that Iron Man, Spiderman, and a floating cape would be stowaways on the spaceship.
The guardians would know not to attack Thanos as he would get the reality stone. In the prompt, the collector didn't watch the movie (!!) so there would be no reason to expect that the scene wouldn't play out like that. Did Nebula watch the movie? Does she know that a solo assassination mission would fail and that her memory banks would betray her sister? Important questions.
I'd argue that the guardians would still split up but head toward earth and join the avengers. Xandar didn't watch the movie so they lose the power stone. Thanos doesn't get the soul stone as Gamora ran away from him. I'm going to argue that Thor's fate is the same - by the time they realize that they're on a spaceship that can't compete with Thanos, and that Hulk will be beaten, they can't prep much. Maybe Heimdall can teleport everybody to earth in the best case scenario.
If things proceded to the point of the Wakanda fight, I don't think Thanos would waste his time with a blitzkrieg attack. He'd nuke the planet from orbit until the avengers gave the stones up willingly.