I got this lovely reversible olive drab silicone coffee dripper and mug set locally (from Lazada Philippines). Rivers is a Japanese brand. The side with the fat ribs flows faster, so I make sure the fat ribs are in the inside of the dripper. It’s great for camping.
Looking at your picture, you used medium to coarse, yes? Have you tried finer ground?
About 18 clicks on the Timemore C2. Medium, yes. I usually stick from 16-18 clicks when brewing this way.