Beyond that, we have an issue where corporations and high-net worth individuals aren’t paying taxes, which could prevent onerous taxes on the middle class. No nation really taxes the rich (cf. the Panama Papers).
Basically, if you have enough equity, a bank will loan you the money you need, while you can leave those stocks untouched. You don't have to pay any tax, let alone the extremely preferential capital gains tax.
The Whitehouse in 2021 estimated that the 400 wealthiest families paid around an 8% income tax (https://www.whitehouse.gov/cea/written-materials/2021/09/23/...).
US has a tax gap of perhaps $1 trillion, and much of that is wealthy Americans who are too hard to pursue: https://www.nytimes.com/2021/04/13/business/irs-tax-gap.html. That could be 50% of the bill if we were able to cut healthcare expenses by dropping insurance companies, removing pharma control of prices, etc., to try to attain similar OECD healthcare costs.
The US is in a unique situation. We have to both reduce the amount of rent-seekers within the healthcare system while increasing the taxes we levy on the wealthy. Universal care might mean an increase in taxes on the middle-class, but universal care will ultimately reduce their expenses since it's more efficient.
PS. Please don't attack people personally: it's much better to say, "This comment does not account for X," than "You seem very uniformed [sic]?"
PPS. If you need a poignant example of the failure of the US healthcare system, look no further than maternal mortality rates. What a disgrace.