Do restaurants always cook chicken to 165F throughout when frying on cast iron?
Serious eats has a detailed explanation of chicken cooking temperatures available https://www.seriouseats.com/2015/07/the-food-lab-complete-guide-to-sous-vide-chicken-breast.html
The short answer: if you are pan frying, grilling, or roasting a chicken  to 165F, it will be guaranteed to be pasteurized to US safety standards, no matter what else you do, and entirely over cooked in the process.
Lower temperatures for longer times also meet US safety standards without overcooking, but are not as easy to measure.
I've sous vide cooked chicken to 136F infusing flavors and making it safe, then finished on an open flame for less than 30 seconds. Besides the very surface, the great bulk of the meat was never anywhere near 165F.