Was born with super small feet in the 1st percentile as well as hands due to a benign genetic issue. Totally healthy but shoe shopping is always awkward. Have decent balance and can walk and run fine as my calf muscles are quite developed to compensate. No, the myth isn’t true.
46 shouldn’t be that hard to find surely? In my experience most shoes go up to 46 but availability drops off dramatically after that. I use 48/49 and had a lot of difficulty until the government decided to subsidise custom footwear because of my flat feet.