Edit: just read other comments pointing out the healthcare thing. Hire a professional.
Honestly, authentication is not that hard. There are many ways to do it, all with valid trade offs.
What you need to know is what your AUTHORIZATION story will be. Can anyone who can hit your API receive all data? Otherwise, you either need some kind of stateful access control or some kind of bearer token granting certain kinds of access. If the latter is simple enough for your use-case, then JWT, despite it's naysayers, might shine for you. Otherwise you can just use about anything since you'll be looking up what they can access in a DB anyway.
Honestly, authentication is not that hard. There are many ways to do it, all with valid trade offs.
What you need to know is what your AUTHORIZATION story will be. Can anyone who can hit your API receive all data? Otherwise, you either need some kind of stateful access control or some kind of bearer token granting certain kinds of access. If the latter is simple enough for your use-case, then JWT, despite it's naysayers, might shine for you. Otherwise you can just use about anything since you'll be looking up what they can access in a DB anyway.