Well, what you've already done should take care of most of the problems I can think of, but you could have a clogged hose somewhere, or you could be low on antifreeze. Also, if you have a damaged or aftermarket front grill, you may not be getting enough airflow, even with the fans. Also, something else you could check is your temperature sensor. It's possible that the sensor is bad, and is giving the computer false values, making you think the engine is overheating when it really isn't. That's really all I can think of, unless you live in the desert or something. You might just have to bight the bullet and have a mechanic look at it. I'm sure you're frustrated, so good luck. Also check the water pump a water pump not circulating will cause the car to build up heat and over heat. Check to see if the radiator is cold if it is and you have no heat that could very well be it. If those are the case and the coolant reservoir is hot that is a water pump. Also if you can squeeze the top hose and hear or see the coolant is filling up in the collant tank cause of that you know you don't have a clooged radiator normally. A water pump doesn't just have to leak to be bad. Also double check your tail pipe for buring of antifreeze smell it and check your oil level to make sure its not mixing.
you probably need a new radiator and get the engine back flushed while your at it.
check your fan clutch if its weak it will overheat
have you flushed your radiator or changed the thermostat it could be stuck
Test gauge function with a mechanical gauge to get actual engine temp.
Either the water pump impeller is loose on it's shaft, or you have a leaking head gasket.
If your radiator isnt leaking and car is having a over heating problem and coolant spewing out. Chances are your thermostat needs replaced. possible the radiator needs to be flushed. But more likley its thermostat
you might want to check for a blown head gasket or a cracked head or block. espically if it loosing water out of the radiator with out leaking on the ground.
The radiator may have debris that needs to be flushed out.
You might have bad actuator that opens and closes airways.
change your thermostat.
Have you flushed the heater core?