AFAIK, the install source is the last one to have installed or updated an app on any profile.
If you copy an app into another profile, the new install source on all profiles is the one that installs it in the new profile (grapheneos if you install through the system, or Files if you install it via the APK you copied into the new profile, etc).
Re-install or update the app from Play Store in one profile, and the install source will be Play Store in all profiles where the app is already installed.
In other words, last install source on any profile = install source on all profiles.