Medicare for all is one of the most important policies to alleviate pressure on lower-income people. Even for the middle class, the freedom to change jobs or take time off without fear of disaster will take such a load off of society.
Alternatively, the Canadian system does not require any sort of insurance-like payment to access all but a few parts of the healthcare system. While wait times are a bit of a problem for non-emergency care, Canada pays ~1/3rd of what America pays for healthcare. That leaves significant funding available to improve on that system simply through more doctors and and better equipment availability, while still being much more cost-effective than the current system. It should also be extended to dental and drug insurance, but again, there is ample funding available to accomplish that and still remain cheaper than the current system.
Medicare For All is most similar to the Canadian 'insurance', and the best candidate for healthcare reform. There are some important conditions for it's success however---the restrictions on price negotiation must be removed; equivalent private insurance must not be allowed; and taxes must be increased to appropriately fund the system. Ignoring any of these will allow the system to be corrupted by wealthy interests (of HN includes many), and could result in a system deliberately designed to fail. Rich people _must_ use the same healthcare service as poor people, aligning incentives among all socio-economic classes, ensuring the system remains effective and well-funded.