Eternals is by far the worst. It's both too long and too short, it's boring, the pacing sucks, the story makes no sense, it pretends to be deep whilst bringing nothing of substance to the table, it has too many characters and almost all of the jokes fall flat. I've seen every MCU movie in the theater and this was the only one I severely disliked, to the point where I kind of regret seeing it.
Captain Marvel is second for me, purely due to the cringy, sloppy writing, in your face political messaging that interferes with the plot ('Smile Honey', 'I've got nothing to prove to you' and 'I'm just a girl' come to mind) and an absolutely unlikable main character, which is a shame because I like Brie Larson outside of this movie. It has some good moments here and there, It's certainly a more competent movie than Eternals, but overall I just don't ever want to see it again.
The Incredible Hulk, Iron Man 2 and Thor 2 are flawed, but still enjoyable to me, although they are at the lower end of my list, and pretty much everything else varies from good, to great, to amazing.