I finally finished watching this. It took about 5 sittings to get through it, so I'll admit my viewing experience was less than ideal. I prefer to watch movies for the first time without interruption, since that's how they are intended to be seen, but if I did that with The Marvels, I would've gotten even more frustrated while watching it. At least taking breaks let me try to approach it from a better perspective.
I still think it's not a good movie. The actors do a good job, though I still have no interest in Carol Danvers or Monica Rambeau (or her mother) as they exist in the MCU. I never read a lot of Carol Danvers stories in the comics, but the character was more interesting to me in the 80s, when she had her powers and entire psyche permanently stolen by Rogue (while she was still in the Brotherhood). That's also what I missed from Rogue's character in the X-Men films - her dual personality, with Danvers always there, in the recesses of her mind, and the guilt she felt over it and fear it could happen again. Plus, it added flight, mega-strength and invulnerability to Rogue's powers. But I digress.
As I said before, the whole production looked cheap, less like an MCU film and more like an MCU series on a strict budget. Costumes, sets, fight choreography, lighting, etc., all looked below par. I don't know why it was directed to look like a sitcom. Everything lacked a feeling of depth, and that's not even mentioning the script, which was a mess.
My biggest problem was how Captain Marvel was "Nerfed," for lack of a better term. Previous screen appearances presented her as possible the most poweful hero in the MCU, so much so that they had to basically wrote her out of most of the Infinity saga because she was too powerful. In The Marvels, she can't handle the most basic of bad guys. I know the idea that the thee "Marvels" having their powers intertwined was probably meant to give a rrason why Carol couldn't let loose, but all she should've needed to do is tell Monica and Kamala to sit back and not use their powers so she could take care of things unfettered.
Also, the villain was supposed to be a huge threat, yet they ended up easily defeating her in like 2 seconds at the climax of the film.
And the main motivations for the villain, and also the reason for Carol not returning to earth (disappointing Monica and creating a rift between them) was Carol destroyed the AI the Kree society relied on, causing a civil was that destoyed their environment, which led them to hate Carol, calling her "the Annihilator," which made her felt gulity. Yet, she just decides to fix that at the end, and does so easily - once again demostrating her immense power that was not on display earlier in the film (like when she gave up and told Kamala "we save who we can" when clearly she could've saved more, she struggled against common soldiers and their vehicles, trying to outmaneuver them by piloting a spaceship when she could've just grabbed the whole ship and flew Kamala and Monica away safely). It's not like she had he powers blocked. She didn't suddenly get more powerful - she had the same powers she had since she destoyed the Supreme Intelligence. She could've fixed things years ago, preventing all this from happening, including the rift between her and Monica (which is forgiven pretty quickly).