Endgame did a lot of great things including breaking the "formula" a lot of super hero movies seem to follow nowadays. This being said, it contained some awful story telling and character development.

The Russo brothers merely wrote out how they want the movie to end, and made a connection to the present MCU. The movie is completely plot with very little / poor relationships and character development. The gates opened in many times to have a great breaking of relationships and massive character development, but the Russo's instead took those opportunities to make action sequences rather than anything that the audience would feel for more than 3 minutes afterward, a mere portion of an over three hour movie.

Also, another point to note, there is a portion of a scene which scream "women's equality" at the viewer in the most cheesiest and cliche way which completely breaks whatever connection the viewer is currently having with the rest of the scene. The proper way to handle equality of women in movies is to just make them cool, and not overdo it to the extreme this movie demonstrated.

If your a fan of the MCU, definitely watch it. Otherwise I would recommend to avoid it.