Jumping from 1.0 to 0.9 is far too big a jump for changing the extrusion multiplier. Change in steps of 0.01. I'd aim to get to around 0.95......but that's a complete generalisation!!! Its make a small change ,,,,,and look to see if there is any difference. Make another small change.....and see what happens then.
Try a vertical lift of 1mm....and again, adjust in small steps. NEVER jump from one extreme to another!
And according to Google searching, your printer's minimum layer thickness is 0.1mm. I'd use that for fine finishes...
And a final thought. NEVER make a change without understanding the effect of making the change beforehand. Maddly tweaking settings about is not the way to understand what settings do. And don't change two settings at the same time....if there's a difference, which change made the difference???