Magura HS33 brake pads strongly pressed against rim, despite adjusting screw fully open. Too thick? Wrongly installed?
On the brake cylinder, the brake shoe holders are pushed too far toward the rim.  To pull them out:


Unscrew the adapter screws (marked in red in the image);
Pull the brake shoe holders away from the rim;
Rescrew the adapter screws.


Repeat for the other side (the other side is quick release, so only has one adapter screw).  Magura recommends that there should be 1–1.5 mm space between the front of the brake pad and the edge of the rim.