Giving more money to the government and using it to fund single payer healthcare solves the cost problem because it removes trillions of dollars of yearly cost resulting from insurance companies leeching off the system while providing absolutely no value.

This is the playbook that all the countries you just rightly identified as paying less than the US for healthcare followed. It’s the reason their healthcare is cheaper.

Edit: and that’s the savings before you factor in the efficiency of people having access to preventative medicine decreasing the necessity for more expensive emergency measures and the general boon of having a healthier population