That doesn't guarantee A+ CinemaScore and $1.9 billion without China, ever heard of The Flash?
It still made a lot money and multiverse was a big reason for it.
Literally your argument was that "the GA really doesn't dig multiverse", which is objectively wrong. Why are you shifting the goal post to something that's subjective and you're in the minority in? Every MCU multiverse project (NWH, Loki, What If...?) is critically acclaimed with the exception of DS2 which is still fairly decent received by critics and mixed by audience.