I've been daydreaming about starting a US company around the idea of being able to hire a "medical coach".

Not a doctor, and not a case worker, but someone with a deep knowledge of the American health care system and infinite patience. A trusted person to take you to and from appointments, to chat with you about how things are going, and handle paperwork.

It would be expensive, but I think it would pencil out for most working professionals who don't have the time or energy to navigate everything for themselves or for a loved one.