How do I retrieve deleted Photo on iPhone 12 Pro

Look in the Recently Deleted album: Delete and hide photos and videos on iPhone - Apple Support

To recover deleted photos, do the following:

1. Go to the Albums tab, then tap Recently Deleted under Utilities.
2. Tap Select, then choose the photos and videos you want to recover or delete.
3. Choose Recover at the bottom of the screen.

The Recently Deleted album is holding the photos for up to 30 days. for you to recover them.

After that they will be permanently deleted. If You deleted them from Recently Deleted as well, you cannot recover them any longer. Then you need to use the backups you made before the photos got deleted.

What kind of backups are you keeping?

Icloud stores deleted photos and videos up to 30 you can set your trash file to hold them up like 90 days just trash them in case you were hasty when you deleted give yourself time to breathe through before you permanently eject them