> If a user is signed in with a personal Apple Account and Managed Apple Account, Sign in with Apple automatically uses the Managed Apple Account for managed apps and the personal Apple Account for unmanaged apps.
no, but many apps can independently use a different Apple (nee iCloud) Account specifically for that app.
that said, you can create multiple users per macOS device, and each can have a different Apple Account. that's a nightmare, because some significant areas of device management assume a single Apple Account. So for example you can use a 2nd account to get around Activation Lock in some cases.
However, for iOS and iPadOS, the answer is “Sort of”.
As taken from https://support.apple.com/en-gb/guide/deployment/dep4d9e9cd2...:
> If a user is signed in with a personal Apple Account and Managed Apple Account, Sign in with Apple automatically uses the Managed Apple Account for managed apps and the personal Apple Account for unmanaged apps.