Thanks, both of you.
Your advice helped a lot, I've asked my GP if she could recommend a new pulmonologist that would be good in my special case.
I have some trouble explaining why I need a pulmo, even though I have a good neurologist, specialised in MG already. My GP said: if you have breathing problems, due to your neurological disease, you have to see your neurologist, not pulmonologist. Because when you have double vision, you don't see an eye doc, but again: your neurologist.

Well, that seems logical to me.
So, I don't have sleep apnea, "only" pure weakness due to MG. Does that still require a pulmo, or does my GP have a point?

Oops, forgot to mention: I'm already being checked regularly by a cardiologist. My heart rate is kind of high, not terribly, but "above average", and I have some mild prednisone - induced - heart problems. See him at least once a year. Never mentioned my breathing though (?)