Is it possible to remove the app icon on iOS?

No. iOS does not allow an application to hide its icon.

We suggest users move the HiddenApp icon into a subfolder (unrelated to security) to make the app less visible.

We also suggest setting up iOS App Restrictions to prevent the thief from removing the app. You can do so under ScreenTime by following these steps:

1. Go to Settings
2. Screen Time
3. Use ScreenTime Passcode
4. Content and Privacy Restrictions
5. iTunes & AppStore Purchases
6.  Enter Passcode
7. Set Deleting Apps to Don’t Allow