Why does it matter what movie it was for, it hypes the character either way. It takes the most important advertisement slot and uses it for her solo movie, fans get excited and watch the movie, following that movie they expect to see her in a prominent endgame role.

The story was rushed, as in the time frame of the movie, the 2 hours spent watching it felt like she didn't get enough character development. The focus constantly shifted to other characters and a conflict far too big to share the screen with an entirely new character. We had to be introduced to a cosmic war, alien races interacting with the planet, early SHIELD operations. Where's the young Carol that overcomes her struggles, that we're inspired to root for, that we see level up to become a hero? We got flashbacks and a fumbled mess of an origin. Just my opinion, but there's a good reason she got a less prominent role in Endgame, her first solo movie did not establish her enough to stand with the main cast, she as well not have been there at all. Her purpose was to get Tony back to Earth and destroy Thanos big ship, that is everything she accomplished and both of those can be rewritten to happen another way.

Personally I would have put NO end credit scene following Infinity War and gone in an effort to have the most solemn mood possible. The way it was set up made people believe it would be Capt Marvel to the rescue after Fury got dusted. Then following Endgame would have had a post credit scene introducing a Captain Marvel, probably by tracking down a Skrull infiltrator.