One theory I heard was ultimately he’d argue that the conduct he’s charged for continued once he was in office (e.g. he cut Michael Cohen a check while he was President) therefore his “absolute presidential immunity” should kick in and cover everything.
It’s horseshit, just like the immunity claim itself, but really it’s only meant as a delay tactic. Since it failed watch out for more attempts at delay. Either appealing the denial of this motion or something like a motion to withdraw as counsel from his lawyers after he fires them and tries to ask for 6 months delay to get new counsel up to speed.