Of the dommes who post at max or domina, I would not even know where to look to see if they had an alter ego who was in videos as a sub.

If a domme stated or her website that she has been a sub or taken punishment, then my reaction would be to esteem her and to take her more seriously than 50 to 70% of dommes who advertise or have a site.

She would simply need to make clear that she will be in control of the sessions!

There are guys like me who think that getting caned or whipped is good "for you" spiritually, emotionally or mentally.

So, your friend or acquaintance has a leg up.

Most dommes do not survive as dommes more than 18 months. At least, so says one of the best.
They quit, they leave, they have no repeat customers or who knows.

A domme who has been punished has a chance of success.