The Z axis not level issue is usually going to either be hardware or allignment. To get them bacl where they should be, run the Z axis down to the bottom, then power off the machine and unplug the Z motors to prevent electromagnetic pulse back into the board. Now manually turn the right hand motor until the distance with calipers from the top of the lower Z axis bearing to the bottom of the Z axis leadscrew nut on that side is identical to the measurement from the other side. Then reconnect the motors and power the printer back on. Then re-level your bed. You will also want to check for a loose Z axis motor coupler. You should have at least one of the two setscrews per top or bottom of the coupler resting in the center of the flat spot on the motor shaft and the leadscrew shaft, with the other screw on each side down tight. If any setscrews are missing, replace them before operating the Z axis.
After that, lubricate the Z axis leadscrews (and just the leadscrews, not the smooth rods) with White Lithium Grease. Then run the carriage up and down a few times. If the issue occurs again you either have another allignment issue, a failing Z motor, or your measurement was off. Check that the leadscrews are up and tight to the top of the upper bearing, and the lower Z motor mounts are all the way up and the same height on both sides. Then check for frame square. You may want to also try loosening the idler side X axis rod retaining bolts and running the Z axis up and down a few times to make sure that isn’t pinched or bowed out.