So I'm reverting to type and have a massive review of Endgame in the works, though my job is keeping me too busy to just crank it out, but I actually have an interesting insight I'd like to share here.
Depending on how inclusive your definition, Avengers: Endgame is not actually a movie. Specifically it isn't a cogent, coherent Story being told via the visual medium. It is a Coda to a long series of movies , brutally stapled to a demi-plot 'third act' for closure to Infinity War (that is to say: you can treat Avengers: Infinity War as being told in a Three Act Structure, with the movie itself ending in Act Two, and EndGame providing the missing Act Three.)
While a perfectly enjoyable, if somewhat hollow, filmic experience Endgame mostly exists to trigger Nostalgia Feels and provide closure for well established characters. In some ways it is almost as disappointingly transparent a shallow cash grab as the new Star Wars films, being elevated entirely by the virtues of actually being entertaining and having developed characters. It its own distinct way it is as much a warmed over rehash... this time of all the previous films... as The Force Awakens was (for its single film).
I actually liked Endgame, however.
I will have a fuller explanation up probably by this weekend, which I'm sad to say will probably take most of the weekend to read, as I am nothing if not exhaustively thorough.