I would be curious to know what the A/C pressures are when this happens.
If it only overheats when the A/C is on and in stop and go traffic, I’m wondering what the high side pressure is at that time.
If there is excessive pressure, that could be putting enough of a load on the cooling system that it can’t dissipate enough heat causing it to overheat. Again this would lead back the condensor restricted/dirty or the radiator having a internal restriction.
Willey