so right now, it appears nothing is wrong with your cooling system.

you need to get over what the gauge says.
IT IS NOT CORRECT.

if your IR gun shows under 200 or 195 ish, when the thermostat opens, and it maintains that temp, you don't have any cooling issues.

your old gauge just reads there now for your operating temp.

The drop in the gauge you see may not be much degree wise.
unless again, you are seeing a huge drop with the ir gun.

Either way, I don't see a problem, unless the temp the ir gun shows is way over 195 before the thermostat opens, or you start going above that at the radiator.

your gauge is just not reading where you think it should and it is making you chase something that isn't wrong.