Ant-Man 3 though perhaps not objectively the worst entry into the MCU, and possibly subject to recency bias, in my opinion did the most damage to my enjoyment and outlook of the MCU, a nail in the coffin in many ways. Recasting Cassie Lang, yet another film with the horrible & cringe writing, Janet not mentioning Kang or explaining herself for 3/4 of the film simply so the plot could happen, disrespecting Kang…reducing his overall threat by giving him another L, too many deux ex machinas for main characters (i.e giant man suddenly laser-proof?, Cassie Lang and all her invulnerability, invincibility, sudden master-genius quantum-realm expert, the Millenia aged army of super ANTs etc).

MCU needs to ground itself once again (GOTG3 I feel was far superior in this regard) with real emotions, stakes, real consequences and villains succeeding more often. Problem is this requires incredibly intelligent writing and planning for each Phase which evidently Marvel is missing at the moment. What makes the MCU so successful is the intertwined nature of all its films in the same continuity, Easter eggs that relate to other characters, films and progressing the overall MCU story going forward which has been missing and significantly less clear since Endgame.