What PowerApps needs is what Power BI already supports. Multiple views for "Page" or "Phone".
The Phone layout starts out as simply a blank screen or canvas that has access to all the same data and permisions as the initial (PC or tablet) page. The app figures out which one to display when the app is opened.
PowerApp already knows the 'platform' that the App is opened on - because it shows up in the Apps Analytics:
It should not be a major reach to work this functionality into PowerApps. Having two separate apps, datasets and permissions for the same functional app is not sustainable - especially if you have dozens of apps to support over time.