If any doctor or hospital administrator tells you that Medicare For All is a a good thing, they would be kidding you. On the average doctors and hospitals have their services discounted about 20% by Medicare. Many services are more deeply discounted. This information is not published.
There are two different ways to purchase Medicare coverage. You can purchase original Medicare and supplement the various deductibles with a supplement plan that is sold by an insurance company. The biggest part of the medical bill is still paid by Medicare.
The second type of Medicare coverage is called an Advantage plan. Advantage plans are very similar to HMO plans. Medicare pays the insurance company/Advantage plan a flat fee for each person that chooses their plan. This is called capitation. The amounts vary by zip code but it is about $600 to $800 per month per person. Insurance companies are not likely to publish these rates. The insurance companies pay doctors and hospitals for services instead of Medicare. Most Advantage plans offer prescription drug coverage. When someone tells me that they do not have a premium, but they also pay a co-pay for services and a larger co-pay for hospitalization. Their prescription drug coverage is usually quite limited.
I want to point out that this is not an entirely bad strategy.