could anything else be adding extra vibration ?
noisy cooling fan for example ?
Also clean ALL the rods. Not just the z-screw itself but the guide rods as well.
basically when I do a clean (one is due) I wipe down every guide rod and the screw.
You can actually hear the difference in the sound the printer makes afterwards.

Your settings look fine, what make is the pla ? And is this the same roll that worked fine before the problem started ?