Could have no thermostat, mine was without one when purchased. Overheat in summer, too cool in winter.
Do check the monovalve solenoid's diaphragm for a tear, this typically causes loss of heat when vehicle is in motion. They are $50 or less to fix, and simple. Maybe five minutes.
Your lack of heat to your feet is due to the leaks in the HVAC, most likely the three pods behind the glove box area. Buy a MityVac to test properly. Pull a vacuum on them to test. Figure around $175-200 for the parts and about an hour to install if your first time. I can do them now in 20 minutes at the most.
... this also plays with your A/C come the summer.