Configure SSO for (existing) Enterprise application in AAD

We are preparing to migrate from ADFS to AAD. For this we are registering the Relying party trusts from ADFS as Enterprise applications in AAD.

Some of our SaaS applications were already present as an Enterprise applications because they have an App registration (to provide the Saas application access to the graph api). If I'm not mistaken Azure creates an associated Enterprise application when setting up an App registration.

This auto created Enterprise application does not have an SSO blade. Adding a second Enterprise application (with SSO) is also not possible because the Entity ID is used by the auto created Enterprise application.

Is there another way to enable SSO on an existing Enterprise application?

Thanks!