I would comment as follows.

Iron Man - sort novel for setting marvel tone but mostly banal action movie

Iron Man 2 - banal action movie

Thor - banal action movie

Captain America: The First Avenger - particularly banal action movie

Marvel's The Avengers - banal action movie

Iron Man 3 - banal action movie, sort of interesting to see protagonist suffering PTSD anxiety from being a superhero

Thor: The Dark World - banal action movie

Captain America: The Winter Soldier - first interesting take. Patriotism is not the same as government obedience. Real fight choreography approaching a soft john wick.

Guardians of the Galaxy - Early rock and roll aesthetic pretty interesting

Avengers: Age of Ultron - banal action movie, perhaps mcu lowpoint

Ant-Man - superhero heist movie, literally deconstructs larger than life superhero tropes. I think thumbs up

Captain America: Civil War - by this point doing the mcu's own thing, which is novel, but probably not interesting outside

Doctor Strange - banal action movie

Guardians of the Galaxy Vol. 2 - aesthetic still feels mostly fresh.

Spider-Man: Homecoming - super down to earth high school drama, frustrated working class villains suffering the fallout of superheroes, seems interesting to me

Thor: Ragnarok - great film, very genre savvy. Rare achievement to make godly strength brutes feel really engaging to watch. Taika Waititi is a genius.

Black Panther - pretty good. interesting aesthetic. directly addressing racial tensions.

Avengers: Infinity War & Endgame - Mostly fan service and not too surprising but honestly still novel.

Ant-Man and the Wasp - Ehhh I really don't remember

Captain Marvel - Beginning had some great hard sci fi imo. Thought the ending message of newly apotheosizied female not needing to prove herself to her evil male mentor was a solid take, whereas a classic "mano a mano" kind of showdown would be so typical of the genre

Spider-Man: Far From Home - Villain emphasizing themes of the power of deceptive media? heck yeah.

Wandavision - Really bizarre and interesting start. Unfortunately non-self-aware conclusion

Falcon and Winter Soldier - Active discussions of race and the problematic nature of superheroes being supremacists? Very good.

Loki - kind of a super cliche topic (time cops) that is also somehow really rare? eh.

honorable mentions for Logan and Deadpool for being just great; and the Amazing Spiderman for its excellent aesthetics despite terrible writing.