If Marvels makes 700, it would match BP: WF’s high drop of 38%, and that without its star. So if Marvels drops that much or more, it very much should be viewed as a disappointment.
Apart from Ant Man 3, everyone is ignoring that since 2022 (i.e, post pandemic), every other MCU movie has made at least 750 WW (and most of them didn’t get a China release, like Marvels will).
IMO, just because Ant Man 3 failed doesn’t meant we should expect the rest of the MCU to struggle. The performance of MCU movies before or after don’t support that.