First, disconnect the lead screw coupler from the z access motor shaft. This should allow the motor to turn freely without any tension from the led screw. When you press the Z home, does the motor turn freely? (you can manually press the z-stop switch by hand to stop the motor turning if it does).
If yes, re-connect the z access coupler and lead screw, and check that the lead screw is properly aligned. Does it move by hand without much tension?
Lastly, swap the z motor driver with the x motor driver and press the z home button. Does the z access return to home properly?
This should tell you whether the motor, motor driver, or lead screw are giving you problems. Too much friction on the lead screw (badly aligned) will mean there’s not enough voltage in the Nema17 motor for it to turn the lead screw.
If, after swapping the z & x driver cards it works properly then possibly a new driver is needed for the z motor.