I want unused iPhone apps back

Delete apps on your iPhone, iPad, and iPod touch - Apple Support

• Tap/hold on an app and select Remove App, then select Delete App
• Or tap/hold on a blank part of the screen until the apps wiggle, tap the minus sign by the app, then tap Delete App
• Or go into Settings > General > iPhone Storage and find the app, tap on it to enter the app menu, select Delete app at the bottom

meaning that when you find the app in the App Store it says 'Open' rather than allowing a download?

If so, then you never actually deleted the app, you just 'removed' it from your Home Screen.

From your Home Screen, swipe left until you get to the App Library.

Swipe downward and you'll get an alphabetical list of your apps.

Locate the app in the list or type the app name into the search field

Once you've located the app, tap/hold then drag it and it'll pop out to your Home Screen

Organize the Home Screen and App Library on your iPhone - Apple Support

no problem, glad to be of help!