2000 ford ranger v6 3L flex overheating mystery

For a while now I’ve been having issues with my truck overheating. Generally when I slow down, come to a stop, after driving a while. The other I replaced the radiator cap, as coolant was bubbling out after driving far. Thermostat was replaced. Radiator was flushed today as there was some rusty color build up. Added engine oil as it was VERY low the other day. So far I’m still getting the overheating issues and it seems to happen more so when I run my AC. I’ve noticed no significant leaking from anywhere else after replacing the cap. I’m thinking of either the water pump or the fan? But I dont know how to know for sure and I dont want to replace parts that I dont have to as a waterpump alone is $50-60. Whatever help you can toss me would be a HUGE help. Thanks in advance.

Does your cooling fan come on when it overheats? Does the fan come on when you use the AC ? If yes to those, I suspect a plugged radiator. If no, a fan or relay.
If the fan is working you should get a pressure check of the cooling system to rule out a head gasket or cracked head.

The fan behind the radiator does kick on and seems to be working fine? A friend is recommending “air in the coolant system” and to run it for 20 mins with the cap off to pass the air out of it. Thoughts?