She should've been built up more as a character before Endgame
Overall I enjoyed Captain Marvel and even thought Larson did a fine job portraying the character, but I just really think the character would've benefitted a lot more from at least one more solo outing before Endgame.
I've seen people mention how she really hasn't earned her place to defeat a villain we've been anticipating since The Avengers, and I definitely agree. I feel like if she would've been introduced in phase two, and had a sequel in phase three, she'd be more worthy to share the spotlight with all the other heroes that are still alive. To be honest though, I don't think she's written into Endgame as the reason Thanos gets defeated this time around. The original Avengers didn't die for a reason and Captain Marvel or not, I think they'll still be the highlight and the ones who land the final blow to Thanos.