In the following guides you will learn how to create your own login UI with our APIs. The different scenarios like username/password, external identity provider, etc. will be shown.
Are there any thoughts about integrating this into the zitadel UI?
I have the same usecase, which i think is not uncommon in the B2B(2C) field, that would be super comfortable UX, not having to place a separate UI in front of it. Slack, for example, does this quite similarly, it lists the workspaces for selection in which you are registered with a certain email.