Unfortunately, these questions are beyond my skills, I never switched an app into a white app.
Maybe @Aleksi will know ?
Be aware public app are not secure, cf this link: here
Can I secure an app without making users sign-in?
This question comes up occasionally from app creators who want to use one of the public Publisher plans. The answer is no .
Some app creators try to create their own workarounds for each of these levels of security. However, these approaches all have their shortcomings.
1) One authentication method you can use
You can trick the authentication process by using the Data/User Settings (trick is a too strong word for what it implies, simulate should be preferred ).
To do so, set to “Show = ON” an option that will be, for example, a personal ID that you communicate to your user (sms or email).
Then, you might want to related this key to the email provided by the user in another option field, such as email user, and with combination of these two information you grant access to some views in the app, through another option of type yes/no, like “identity confirmed”.
Please remember this is an unsecure workaround.
2) Usage of User Settings
You can call any user settings options using USERSETTINGS(“Option Name”).
In my previous example, you can try :
IF (USERSETTINGS("identity confirmed"),
Please refer to:https://help.appsheet.com/en/articles/2357276-usersettings