If your app implements account creation, then it will likely be taken down unless either your app removes create-account support or the API and your app implement delete-account support, as a user would reasonably expect that you're able to delete the accounts that you create.

If you do not implement account creation, then you're unlikely to be held responsible for account deletion, as a user would reasonably understand that your app is not responsible for creation or deletion of accounts.

EDIT: Elsethread, someone asked "What if I create accounts on the blockchain?", and since it's possible you'll come around to that idea next — the app would have to interact directly with the blockchain, so you'd probably get rejected for a whole array of reasons, such as but not limited to that you're storing account data on the blockchain. And I wouldn't envy you trying to explain why you shouldn't be continuously fined for GDPR violation in the EU, either.