If a 1st order rule of thumb is keeping caloric contents in check, a 2nd order rule doing that for nutrients individually, I wonder if someone knows a good but easy third order rule of thumb that takes into account processing.

Something like "when two foods have roughly identical nutrients, prefer the one that has ingredients you could buy or make at home" might either not help cause there are no two such options to choose from, or it's too obvious (fresh pizza at the supermarket is worse than a handmade pizza)

Is there a good rule of thumb that helps you pick relatively healthy foods in a world where many foods are ultra-processed already, and can't really be avoided?