oauth2-github VS php-saml

In regards to oauth the phpleague packages are fairly popular. Again, the flow requires some redirect dancing so not something that can be (simply) just a single boolean-returning method on the PHP side. Additionally, oauth is a relatively weak standard (Especially where you want to verify identity) in which case platform specific actions/tweaks are needed hence why most use platform-specific oauth libraries. OIDC builds upon oauth to standardize the flow, including getting the identity, but it isn't supported by all platforms offering oauth.

I use this library for SAML. The trouble is SAML is quite complex with a lot of options, and the journey requires you to send off the user to the IdP in the correct way, then receive them back in the right manner (Which is often a POST back to your app so can take some extra dancing if you use samesite=lax cookie-based sessions). Additionally, you'd often want to serve an endpoint for your app's metadata. So not really something that can be served by a single method returning a boolean.