Jungle Cruise is an untested property that has now been given a prime summer release date.
Just today, it was announced that Disney’s Jungle Cruise movie was essentially taking over a release window where an Untitled Marvel movie had been set.
It could be that Disney is just very high on Dwayne Johnson’s new movie and wanted to give it a bigger date than next October, or it could be that Disney needed to fill that hole with something because the Marvel movie needed to be pulled, and it was available.
That film has been taken off the calendar and not given a new date, so the current MCU schedule isn’t just being shifted around, it appears to be going through real change.