The VP is selected by the party leadership, not the presidential candidate. That’s why it’s not unusual to have a President-VP ticket where the two candidates can’t stand each other.
Is it the head of the RNC? Because that's Lara Trump and Michael Whatley.
Is it the Speaker of the House and the Minority Leader in the Senate? Because Mike Johnson is on "Team Trump" and Mitch McConnell is a lame duck.
Who is the "party leadership" that you speak of?
-PJ