It's known director Anna Boden ruined the character of Mar-vell in the Captain Marvel movie, which filmed after The Avengers: Endgame, as she changed the iconic male character from the comics to a liberal PC SJW female character.
The original plan was to use Mar-vell and cast the character as a male, but "late in development," co-director Anna Boden came up with the "suggestion" to use Annette Bening as Mar-vell, a female; Boden has also described her Captain Marvel flick as a feminist, humanist movie.
What's interesting is that the Bri Larson costume used in Avengers: Endgame when she has her short hair (again which filmed before Captain Marvel when Mar-vell was supposed to be a male character) is based on the original design from the comics of the Mar-vell suit (see below).
Since Boden changed Mar-vell to a PC character, we can guess the original plan was to have the male Mar-vell character in the movie be some sort of inspiration for Carol Danvers, but of course, since Disney, Marvel Studios, Feige and the directors wanted Captain Marvel to be a feminist and humanist movie, they couldn't let that happen, so they removed Mar-vell and changed the male character to a female character for their PC agenda.
Credit to the Russo brothers as they kept the Mar-vell-inspired comic book costume in The Avengers: Endgame.
With the re-release of Avengers: Endgame, the Russo brothers posted new behind-the-scenes pics on Instagram from the flick where it is revealed that the directors went ahead and changed the look of the Brie Larson Captain Marvel costume for when she wore the short hair.
The behind-the-scene images shows off Brie Larson wearing the short hair with the costume having the original red on top and the blue on bottom, but when the short-haired Brie Larson appeared in The Avengers: Endgame footage, the colors were flipped, with blue on top and red on the bottom, which is the colors of Mar-vell from the comics.
As Brie Larson wasn't in Avengers: Endgame that much to begin with, changing the costume was probably pretty easy as it was done through use of CGI. We can also guess that the Russo brothers figured after 30 years, Captain Marvel would probably like new clothes to go along with her haircut, and that the original plan was to be inspired by the male Mar-vell character that was supposed to be in Captain Marvel. (Note: Even if Brie Larson filmed the short-haired scenes during reshoots after Captain Marvel, the Russo brothers still went with the Mar-vell comic book costume, as again, the original plan for the Captain Marvel movie was to feature Mar-vell played by a male actor.)
Check out the images:
Avengers: Endgame Brie Larson Captain Marvel costume BTS image (red top; blue bottom):
Avengers: Endgame Brie Larson Captain Marvel costume in the movie (blue top; red bottom):
Mar-vell costume from comics: