"Correcto"
Folks will spent $hundreds on cooling system parts to fix heating issues,
But don't have, or use, an infrared temp gun.
Being so cheap these days, they should be as common as an adjustable wrench.
Best "tool" to have when questioning accuracy of gauge, digital or analog.

If this were my issue I would get out the infrared temperature gun and find where the overly hot or overly cool areas are. A few years ago I had my '68 RR overheat and puke coolant only when I parked it and it heat soaked. Thought the 26" radiator was good and could see good coolant flow looking in the cap opening, had a new water pump and thermostat, good fan shroud, the right pulleys and everything in order. Pulled into my good friend's driveway and sat there for a few minutes and started puking coolant. He went to his toolbox and pulled out the infrared thermometer and the lower 2/3rds of the passenger's side of the radiator was stone cold as it was plugged. I couldn't believe it. Re-cored it and no issues even with a cammed engine and A/C. Get the infrared temperature gun out and start checking where your issue might be.