SSO Technical Design for Health Tech

I'm seeking an expert to create a comprehensive technical design documentation for implementing a Single Sign-On (SSO) system in our Health Tech platform.

Background:
I am a product manager and working on documentation to communicate with engineers. My company is a provider for wearable care device for elderly needs SSO to offer its first direct to consumer product offering.
The documentation should include:
- How consumers would authenticate/register via a first of its kind (for Current Health) public mobile application.
- Would we offer SSO - with whom and how (SAML/OAuth2)?
- What fields do we need to capture in onboarding (in what order) and how might we validate those for each user?
In the context here, onboarding would mean the process of a consumer purchasing a wearable device like the one we manufacture ourselves, and downloading and signing up for our application to get started monitoring their own vitals with that device and potentially assigning others to monitor themselves as a caregiver.

Documentation Requirements:
- identify key features to meet user/system needs
- prioritize and define scope and goals for the initiative, and trade off decisions
- who it might be important to interact with (and how/ when you’d do this)
- product metrics

Ideal Skills and Experience:
- Extensive experience in designing and documenting technical specifications for SSO systems.
- In-depth knowledge of OAuth and SAML protocols.
- Excellent ability to convey complex technical information in a clear and accessible manner.