Take a closer look at BL bearings on x1/p1 machines. The only thing making them touch the rod is a silicone rod cap or spacer. They’re not hard mounted. The only BL printers that had solid mounted Z screws were the first batch of x1-c’s and they quickly realized the problems it was causing.
I don’t own any prusa machines, but I’m almost positive their upper lead screws are not constrained either.