You need to remove those grey printed pieces from the top of your leadscrews. You have precision linear rods for the z axis to follow. The lead screws should touch only at the stepper motor and at the x axis they are lifting. I cut mine to just below the frame. Install your spacers to set things up and get the leadscrews close to straight, sure. But take them out before you run the printer. And when you watch the leadscrew run out like it does, you should smile big and proud at the energy you are keeping away from your linear rods.