Are flat feet always associated with pronation?

No. I’m a flatfoot supinator. Actually suffer from landing in a supinated position on foot placement and it sometimes tears my ligaments/tendons when I land off a big jump or vault.
I’ve never ever had a problem with pronation.
It may help to note that I usually rely the balls of my feet over my heels.

I have flat feet and I pronate but have never researched a study.

I have “4th degree” flat feet with pronation, the width of my foot at my ankle is wider than the ball of my foot. I remember someone in Jr High gym class that had flat feet but they didn’t have pronated ankles like mine.

I thought pronation is merely the spring effect designed into the foot for walking. The arch is designed to deform and recover with each step. It’s when the recovery phase is missing that the diagnosis becomes “flat feet”.

OK, now I’m confused…

Pronation is the ankle, position on the inside is lower than the outside. See attached article and photo.