How to recover photos if I deleted them?

Review this Support Article:

Delete and recover photos and videos on iCloud.com - Apple Support

If it has been longer than 30 days or you have deleted them from the Recently Deleted folder, then they will not be able to be recovered.

Check your Recently Deleted folder - Go to Photos > Albums, and tap Recently Deleted in the Utilities section. If you emptied the items from this folder they cannot be recovered. They are truly permanently deleted.