I can not unhide apps on iPhone

The app may have been removed from the Home screen and be in the App Library. Swipe left past the last home screen to get to the App Library.

On an iPhone with iOS 14, if the app is on a Home screen, touch and hold the app, tap Remove app and then tap Delete App (or tap Edit Home Screen in the pop up menu, tap the minus sign, then tap Delete App)

If the app is only in the App Library screen, touch and hold the app there and then tap Delete app.

If neither of those options is available, there may be a restriction set on deleting apps. On an iPhone or iPad, go to Settings > Screen Time > Content & Privacy Restrictions > iTunes & App Store Purchases > Deleting Apps.

See: https://support.apple.com/en-us/HT201304#prevent-purchases

that is not what unhide means

when you delete an app it will still show on in your purchase list forever, however you can hide it in which case it will not show up on the list