Just to get off the time travel debates for a second:
As much as "Endgame" was an homage to the entire MCU, I really liked how Endgame really tried to make the "Avengers" movies a coherent trilogy on its own, apart from the other MCU movies. Hence the attention they paid to the characters that they did:
-- Captain America:
Avengers - A man out of time feeling like he didn't have a place in the world.
Endgame - Finds his place with the love of his life, finally "lives life" (or whatever it was Old Man Steve said)
-- Iron Man:
Avengers - Cap accuses him of being in it for himself, not the guy who lays himself on a wire so the other guy can crawl over him.
Endgame - well, you know...
-- Black Widow:
Avengers - she has red in her ledger and wants to wipe it out. Hawkeye is the key to her redemption as he gives her a second chance.
Endgame - Hawkeye ultimately serves her story arc for redemption. His arc only exists to mirror her past misdeeds and her sacrifice a way to finally balance her ledger.
-- The Hulk:
Avengers - obviously at odds with his other half - can't even say his name. Always angry.
Endgame - totally at peace with his selves. Angry no more. (he couldn't even pretend when they were back in NYC)
Thor's arc didn't really play itself out in the Avengers movies, I'd say. (if anything, Loki had more of a story in the first film) His story is the least coherent if you just take the Avengers movies.