Your placeholder site describes a product that suits one of our use cases as well.

Please launch with "Sign in with" for Microsoft as well as the typical GitHub / Google, allowing anyone using an M365 business to allow their employees to poor-man's SSO.

See the "Continue with" section here, for instance:

https://www.xsplit.com/user/auth

Or here:

https://id.atlassian.com/login

Sure! [username]@gmail.com