Mazda tribute 2004 v6

Where do I even start? No check engine lights, but the battery flickers. The alternator is good, and the battery is good. Whenever I turn the AC on full blast, a second later when the radiator fan kicks in, the car loses RPM, and it feels like the car might shut off at any second, but it doesn't. Then the battery light starts flickering. My next option is to go to a mechanic, but I don't want to get ripped off.

Checklist

Alternator is good

battery is good

Radiator fans is good

Serpentine belt is good

I don't see any physical wire damage from the top of the car