Earlier quoted context omitted.
IANAL, but I did health tech for 10 years and had my fair share of interactions with lawyers asking questions about stuff I built. HIPAA applies to the provider. Patient have no responsibility to ensure the tech used by their care provider is secure or that their medical records don't wind up on Twitter. HIPAA dictates that the care providers ensure that happens by placing both civil and sometimes criminal liability…
I don’t think the question is about Zoom’s safeguards which are audited, and as you say almost certainly stronger than HIPAA requirements, but rather whether they can use the stored PHI for product development where the law appears ambiguous.
-De-identify it then do whatever you want with it -use it to provide some service for the covered entity, but not for anyone else -enter a special research contract if you want to use it slightly de-identified for some other specific purpose