Unable to delete app from library

Are you using screen time? If so, you may have restricted deleting apps. See the section titled, Prevent iTunes & App Store purchases

Use parental controls on your child's iPhone, iPad, and iPod touch - Apple Support

Hmm.... it may already be deleted. Try a Forced Restart and see if it is gone.

https://support.apple.com/guide/iphone/force-restart-iphone-iph8903c3ee6/ios#:~:text=Press%20and%20quickly%20release%20the,logo%20appears%2C%20release%20the%20button.

Go to the App Library and tap the search field to open the list.

Touch and hold the app icon, then tap Delete App.

Tap Delete again to confirm.