H1 2023 External Auth Provider / SSO / Member API

Hi Folks! Starting new thread to help others in the same boat. I’m consolidating all my content in Ghost and want to offer a tier for Enterprise customers. As such, I would like to integrate with their SSO solution, which would ideally increase the usage of my content/platform.

How can I integrate something like FusionAuth or Auth0 into Ghost?

Here are all the relevant threads I found, but quite old and no good answer: