Despite what the advertisements were showing, Captain Marvel didn't actually do too much in Avengers: Endgame. Admittedly, they used her enough that she felt like an awesome addition to the movie but she wasn't an integral part of the story, though her few interactions with the team were pretty great. Still, it would have been nice to see more of Carol in the film and a BTS photo teases that there was more to her interactions with the Avengers.
In the pictures below, we can actually see a moment between Captain Marvel and Black Widow. The two characters barely interacted with each other but this handshake seen below would have been nice to see on the big screen. Would it have added that much to the movie? No, but it's not like it would have ruined it either.
What's sad about this is that Carol and Natasha never interact again, aside from a quick chat via hologram technology. This is a real shame since that scene where all the female characters get together would have been better if Black Widow was there but it wasn't meant to be. At the least, she will be getting a solo movie, making her the second solo female lead in a Marvel film.
Avengers: Endgame might still be showing in theaters but the movie should be getting a Blu-Ray and digital release soon.