I'm not going to try to rank the films because at this point its like ranking episodes of a long running TV show - some stuff that was great was partly due to the groundwork laid in earlier films (Civil War) , some stuff that was great was due it setting the stage - where if it failed the whole house of cards collapses (Iron Man, CA First Avenger, Thor, GOTG), some stuff that was great was due to the sticking the landing which is so hard to do (Avengers 1, Infinity War/Endgame). I just can't rank them because I can't separate any single film from the overall narrative and my own sense of how meaningful some were to the overall success of the MCU - it is one thing if IM2 and Thor 2 or Ant-Man are just average, but IM and Cap 1 and Avengers and Endgame had to work. I am still impressed with Infinity War and Endgame which managed to be well thought out, have good character arcs, have some emotional weight, and be interesting and fun and actiony.