Shower Help can’t adjust temp

Can someone please explain how I can adjust this properly. I will post pictures in the comments. My shower only puts out hot water regardless of rotating the temperature knob. It’ll put out whatever I have the heater set to but nothing cooler. How do I get it to be able to provide a range from cold to hot, instead of being restricted to only one temp(what’s listed on the panel). The first pic is the main water heater panel in the kitchen. The second set is the one in the bathroom

Edit for question clarity

Update: for anyone curious it turns out that whoever installed the temp dial “clocked” it wrong. So they put it on where it was already cutting off most of the cold water and only allowing hot. So it would go from hot to hotter with no cold allowed in.

by TangoQ20