That's only for tracking-related cookies/storage as detected by Safari, regular cookies e.g. for authentication or storage of app-related data are not affected by this at all.
> Safari proactively evicts data when cross-site tracking prevention is turned on. If an origin has no user interaction, such as click or tap, in the last seven days of browser use, its data created from script will be deleted. Cookies set by server are exempt from this eviction.
It doesn't matter what the data actually is or whether it is used to track users. Safari deletes it.