I found that the resource “auth0_branding” could be used to create a universal login from Terraform.
However, while this supports the old universal login, it does not appear to support the new universal login.
I would like to be able to manage the new universal login with terraform.
How should this be handled? Or is it not currently supported?
Based on the information present on the auth0_branding resource, this is used for the Classic Login, as you have experienced. With regards to the New Universal Login, the auth0_pages resource from Terraform should be the correct one to use and upon enabling all changes, it should not automatically switch to the Classic Login, as it happens with auth0_branding.