Cannot adjust z offset

After several successful prints with my Ender 3 V3 SE I cannot adjust the z offset. After homing, moving the z offset setting to the extreme position does not move the gantry where I can adjust with a piece of paper. Auto level seems to work fine.

Also, running a bed level test calibration with my original setting of -1.83 does not adhere and gives very thin laydowns.

What can I do???