I cannot move my big toe independently

I don't want to post my feet online, but I have flat feet (from birth) and I have never been able to move my big toe independently. Having seen my mother's outcome, I know I am destined for bunions if I don't work this out.

The only movement that my big toe can do is up and down (following the other toes minimally),

Any products or exercises that anyone can recommend, please?