Low water pressure in shower after turning off main
My guess is there is some debris have plugged the orifices. I would turn the water off pull the cartridge and try to high flow the lines to clear any debris out. In the past I have found rust &amp; scale plugs blocking valves that worked great after flowing, don't forget to check the shower head itself if it has a screen that could be the location where it is plugged if only a shower head (no tub ).