I'd bet that making Captain Marvel overpowered was pretty low on the list of things people disliked about that movie
However, my main point is that the multiverse storyline was not well received by the average moviegoer. Some stories are better in comics versus trying to make them appeal to a mass audience.
The problem was poor execution. When Into the Spider Verse comes out at the same time and does it 100x better you see how it can be done. MCU failed with it. That’s fine there are tons of good stories to tell.