6 Reasons Your Engine Overheating but Coolant Full & How to Fix this problem?

I’ve replaced the radiator, upper and lower radiator hoses, thermostat, water pump, gave it a good flush. Fan works no issues but if I’m driving above 55-60 mph it starts to overheat…when it starts to get too warm and I park it the fan will cool it off, but if I drive below 55-60 mph
No issues

No check engine light is only for malfunctioning emissions

I have a 2012 glk 350 4matic. It was overheating, theres no leaks, no steam, no check engine light on, no weird smells. What else can it be? Shouldn't i get a check engine light if its the thermostat or water pump?