You can believe what you want.
The reality is that courts don't get to just blow off SCOTUS rulings, no matter how much they want to. And if Merchan does not do basic factfinding on the new immunity rule, it's a certain reversal on appeal. The briefing schedule to accomplish that is reasonable.
Many people were doubtful that Trump would be sent to jail before SCOTUS’ decision. Politically, doing this in September is actually much worse for Trump, especially if there’s no jail time.