Shower hot water not getting hot enough
If you are experiencing low volume from  hot water in this valve and have not changed any of the mixing settings from when it worked properly I would suspect a partial blockage in the hot water supply line.

Carefully remove the cartridge from the valve body and look for debris. While cartridge is removed turn the water supply on a bit to flush out possible debris. Reassemble and test for normal operation. Good news your valve body has shut off screws for hot and cold water on it!

A valve repair video that shows a very similar type valve is found here