The movie is really about Thanos, like he's the only one who has a real arc. The heroes are the same start to finish, only Doc Strange kind of changes but it seems obvious that him giving up the time stone will play a bigger part.
Even TDK was about how far Bruce was willing to go, and what he was willing to sacrifice.
This movie was about a villain brehs. We saw what he had to sacrifice, his origin and his aftermath. All of the other plotlines are setup to stop him but fail (except maybe Doc Strange). They really flipped this shyt around
On some Godfather 2 shyt, it even ends the same - Thanos achieved his goal but has lost everyone who was close to him. And had to kill his soul - Gamora being Fredo.