I am using Official PayPal + Ghost integration, which is force me to disable free users. I have set up sign-up as invited only, and the setup-up of a subscription page is integrated with PayPal checkout.
How to override the sign-up link to the subscription page while users try to sign up.
I set up something similar for https://activatorhq.com - I ended up not using portal for sign in/ or sign up, to avoid users accidentally ending up in the wrong place.
Hope there’s a guide to do that, it will help user and webmaster
It’s theme specific. You might want to look at the starter theme (https://github.com/TryGhost/Starter/tree/main/members) , which has some sample code that would be a good starting point for those replacement signin/signup/account pages. You’re going to need to replace each portal link with a link to the appropriate page instead throughout the theme files, anywhere your theme is currently showing a signin/signup/subscribe link…