+1 for the proposal.
We would like to extend this to enterprise scenarios, especially when the browser boots up and loads the RP website without the user and/or IDP context - let us call it a "cold start" use case. We propose to provide options for "cold start" to get the IDP context through IDP registration by being able to read user/IT admin consent from an enterprise policy.
This removes a lot of friction for users and apps with pre-determined IDP in enterprise use cases.