Strange you should post that.
I used to run around the beach barefoot from ages 8-13, while my Dad was fishing from shore, me just chugging around, building firepits, and generally checking out the beach for about a mile N and S.
I had the flattest feet to start, ended up with flat feet after that.
Possibly, it's not possible for someone with high arches to make any kind of judgement or advice for flat feet people. Possibly.
Like the example I used. Perfect complexion 17 year old girls selling cream to make your face look younger. It just ain't right.
Like those two guys.