It seems that the welcome page needs to be enabled so that the callback from social login can work. /self-service/methods/oidc/callback/github Dont know if I missed that in the documentation.

No, but there is currently a bug, where we do not show the error at the end of the oidc flow. You likely have an error in your configuration. If you open the developer tools when starting the flow, then going through the flow, you should see one request to the /callback URL, that contains the error details. A fix for the issue should be available next week, as well.