I don't understand your obsession with the lower hose temperature. The heater circulates fluid from the block and not from the radiator. In a perfect world there isn't continuous flow through the radiator. Cold fluid from the radiator is pumped into the block until it heats up. The thermostat opens after the fluid reaches a certain temperature and flushes it into the radiator which pushes cold fluid in. The coolant temperature inside the engine looks like a ramp going up and down.
The fluid in the bottom radiator hose SHOULD be cold, or you're flushing hot fluid into the engine to cool it. Obviously counterproductive. IIRC you mentioned in your last post that you used an IR thermometer to measure the temp of the upper hose outlet and it was 180 or 190deg F. If your dash temp gauge has it sitting about middle, and the outlet was the right temp, then your engine coolant system is probably working just fine.
Most likely you have a blockage or restriction preventing fluid from getting to the core. What is the temperature of your heater hoses right by the control valve?