My previous car had similar issues.
Water pump, fan, thermostat, etc all ok.

Finally found the culprit.
It was the radiator .. clogged up with dirt that air flow their the radiator fins were affected.
Cleaned the dirt off using water spray.

Problem solved.

Coolant will pass through the radiator channels and the fins is to remove the heat and air flow through the fins remove the heat from the fins. If airflow is not efficient or blocked...heat is not removed from the coolant.