The biggest obstacle to Medicare for All isn't the insurers, believe it or not—it's the providers (hospital corps, pharma, and the AMA). But the AMA is not representative of doctors as a body—many have had the idea that medicine is apolitical drilled into them since med school.
So that's an opportunity to talk to individual doctors about how their actions have significant financial (and thus health!) consequences—private insurance coerce doctors into making choices that harm their patients.
I've spoken to a lot of doctors who just don't know about this stuff—it's as opaque to them as it is anyone. It's fun to talk about Medicare for All with them. I've even done it while on the operating table, as the doctor was slicing open my ballsack. The conversation went well!
the AMA is bad for other reasons too https://www.ama-assn.org/delivering-care/public-health/ama-urges-court-overturn-medical-cannabis-ballot-initiative