I don't really understand what you mean, universal healthcare means everyone has access to healthcare. Increasing the supply of medical facilities and staff is obviously a core part of implementing that in the US. If the government pays for healthcare but there aren't enough beds for everyone who needs one, then by definition it isn't universal.

Either you have long wait times for non-critical things with critical needs met. Or you have short wait times for non-critical things, but critical needs are not met.

I think the latter is a much worse situation, and it’s the status quo. I agree that increasing supply is necessary to solve both aspects of the problem. But keeping people alive should be the most important priority of any health care system, not keeping wait-times short for non-critical procedures.