Example integrations with multi-step config flow?

I’m trying to improve the Tesla custom integration, having trouble understanding the right way to handle a multi-step config flow that can hold multiple user accounts. Are there any platinum examples of integrations that work this way? Essentially, I want the flow to work like this:
Step 1: Enter account ID (email) and choose auth method (Fleet API or Owner API)
Step 2: If email already exists, then stop. Else display 1 or 2 different schemas depending on the auth method chosen in step 1

You could dig on the current core integrations to see if any implements that or ask in the Discord dev group.