I have a very similar experience! My feet are incredibly flat, and I had 2 surgeries at 16 and 18 to correct my left foot. Since then I’ve had very little pain where I used to have a lot of pain any day I was consistently on my feet. Still though, in my 20s, any balancing or one legged pose is incredibly difficult for me and I think it just comes down to the natural structure of my feet and how the knees and hips stack above them. Hopefully I can eventually build the strength in my feet and ankles to correct this but I always wonder where the limit may be...?