Icons of installed apps are not displayed on the device
The features that hide icons of installed apps are the following two profile restrictions.
Check the profile settings.
Profile > Restrictions > Apps > Restrict app usage (supervised only, iOS 9.3+)
This feature makes target apps unavailable (hidden) by specifying them in a whitelist/blacklist format.
Profile > Restrictions > Media Content > Allowed Content Ratings > Apps (iOS 5.0+)
This feature makes apps unavailable (hidden) according to the target age of the app.
There are no other features that hide installed apps.
If neither feature is in use and apps are still not displayed correctly, the problem may be on the device side, so try restarting the device.
Last updated: February 1, 2022