First, your life does not depend on one person.

This MG specialist may be an excellent and caring physician or a total idiot.

He is not the only neurologist in the world. If what he says doesn't make sense, seek another opinion.

Second, being ill sucks. It makes us more dependent on others, it requires that we work around it. It requires painful adjustment to a different way of life.
Some are (relatively) fortunate to have an easy to diagnose and manage illness and some are less fortunate.
some have an excellent response to treatment with complete disappearance of their symptoms and others do not.

This does not mean that you can't find the way to live with your illness, receive supportive care and treatment.

You sound like a very talented and creative person. Why waste all your time watching TV? Why not find the way to do what you want and like. Find the way to feel that your productive life was not totally taken from you.