If both temperature settings are on LO, there is no possibility that the heater temperature sensors are the problem.

A warm driver-side vent indicates insufficient refrigerant entering the evaporator. It is often accompanied by a hissing noise at the center vent.

This can be caused by a low refrigerant charge. However, if the refrigerant charge is not low, there is likely a restriction in the system. Restrictions can be found with a thermometer.

My car had a restriction in the dryer. I recently replaced it, and let me tell you that "freezing cold A/C" is more than anecdotal. I measured 38F at my left-side center vent at idle, 90F ambient, fan on position 4 (just greater than half-way) and recirculate off. Under these conditions, the high-side pressure reads 14 at the pushbutton unit, and the auxiliary fan comes on at low speed.