I use vet wrap to provide extra support for my ankle, but a tensor bandage or any other kind of self adhesive wrap would work just as well
I ride in sprenger bow balance stirrups for the same issue and never have a problem
Try stretching them each time out before you ride. Also, to strengthen your ankles look up some good ankle exercises to build the muscle. If that doesn’t work, check in with someone to make sure that you aren’t twisting your ankles in a weird way while you ride...that could be the source of the problem.