The corruption happens around pricing. There should be fee guidelines in place with caps.

There are fee guidelines. The govt sets caps for the folks who get medicare / public aid.

Insurance companies negotiate rates for everyone else. So much so that when my wife was going to get an Iron infusion the doctor couldnt let us pay for it out of pocket ( we were in a hurry to go somewhere and couldnt wait for insurance) we were told we couldnt pay out of pocket unless the insurance company allowed it

Let that sink in... you cant pay for healthcare out of pocket unless your insurance allows it.

Unregulated pricing is not corruption. Words have meaning.

Adding unreasonably priced hidden items to a bill after the procedure is done without any contract in place beforehand is definitely corruption. The only reason they get away with it is because they have state backing, otherwise this system would have gotten outlawed a long time ago, similarly to how car mechanics can't bill you $100k for simple fixes without warning you about the huge cost before they start working.