If we ignore how important Iron Man is to the MCU, then I'd say Iron Man has to go.

Iron man 3. It did have some good moments and Ben Kingsley was pure gold, and though funny as hell the reveal that he wasn't the Mandarin ruined it.

Probably Thor or Spider-Man.

Spiderman I found homecoming to be somewhat mediocre looking back at it now

Overall Spider-Man. NWH was solid platinum but Homecoming was mid and FFH was kind of a disaster. Throw in the fact that there was 5 (now 6) other perfectly good Spider-Man movies and it's just the least necessary.

I'd say Spider-Man. Homecoming and FFH are two of the most boring MCU films ever. And NWH had it's moments but for the most part it was just meh. So yeah, I think I could live without those movies.

Iron man.

Spider-Man. NWH carried

I personally think that it didn't start good and it started to get better because i mostly like the spiderman part of the trilogy.

Iron man. If we anull his importance to the MCU, his trilogy is boring to me