Single Source of Truth (SSOT) App
Choose an app (among 5 scopes of management in personal productivity) as the single point of reference for all your personal data.
All the other apps under the umbrella of your personal productivity should reflect or depend on this. Derived and different versions of the “truth”.
The one place to refer to and which holds the latest information. Source of “truth”.
P.S. This SSOT is a reverse concept of the original SSOT used in IT.