You can still cache normally behind auth because nextjs's cache is mainly on the server side. This is beneficial because even if user isnt paid try to access paid resource, your auth guard blocks return while the cache is served for the next request

Simplest implementation if you dont have cacheComponents:true in the config is to wrap your data fetching method with unstable_cache. If you are useing fetch() then no need unstable_cache as you can directly configure cache in the fetch parameters

use cache is imo better if you have some part of the app that serves static public content and if u want to delve into partial prerendering.

I did use unstable cache ye but it had 2mb limits and not sure but maybe memory only

I am using keyv library now which is similar concept

What do you mean by directly configuring cache in fetch params

From what I understand there's only 2 ways.
Either unstable cache or
'use cache'

I don't have cache components true. Not sure if it will break stuff