Use Screen Time to hide apps:
Settings > Screen Time
Turn on Screen Time (if needed)
Content & Privacy Restrictions
Allowed Apps
Turn off the apps you want hidden
Use App Library to hide apps from the Home Screen:
Long-press the app
Remove App
Select Remove from Home Screen
The app remains accessible in App Library
Use Hide in Search (optional):
Settings > Siri & Search
Select the app
Turn off Show App in Search
Turn off Show Content in Search
Turn off Suggest App
Use Focus to reduce visibility:
Settings > Focus
Create or edit a Focus mode
Allowed Notifications to limit app notifications
(Optional) Allow only specific apps/people
Use Guided Access (for restricting access to one app):
Settings > Accessibility > Guided Access
Turn on Guided Access
Start Guided Access from within the app to restrict navigation