"All these countries have some variation of a single payer and most provide universal health care.".
This is false. Both left and right seem to believe this. Google "wiki health insurance germany' click on the wikipedia link. Try this with any country.
For Germany is starts with, "Germany has a universal multi-payer health care system paid for by a combination of statutory health insurance (Gesetzliche Krankenversicherung) and "Private Krankenversicherung" (private health insurance)."
For the UK
"Health care in the United Kingdom is a devolved matter, with England, Northern Ireland, Scotland and Wales each having their own systems of publicly funded health care, funded by and accountable to separate governments and parliaments, together with smaller private sector and voluntary provision."
Norway
"In Norway, all hospitals are funded by the public as part of the national budget.[1] However, while medical treatment is free of charge for any person younger than the age of sixteen, residents who have reached adulthood must pay a deductible each year before becoming eligible for an exemption card. The card entitles one to free healthcare for the remainder of that year."
The very closest to single-payer is France, which has excellent health care system.
The important point is that everyone must be covered one way or the other. That's good.
You are correct that the US spends way more, and yes - every person living here should be able to get health care.
Another myth left and right seem to have is that "Medicare"-for-all is great coverage. It isn't. Most people who can afford it purchase Medicare Supplemental or Medicare Advantage, as Medicare leaves a lot uncovered. In my case I also buy Dental and Prescription Drug coverage. Again most who can afford it do too. Medicare does not cover this stuff.
Saying falsehoods like we often do, will only let the GOP correctly pick apart our arguments. Many of us are as ignorant as we accuse the right of being.
My 2 cents - the ACA was designed to be expanded, and to have the percentage of profit that insurance companies keep be reduced. All it takes for these things is an act of Congress and a President to sign. With the next Democratic Congress and Democratic President this will happen. VOTE