The best way to "recover" a photo is to never lose it in the first place. Users should verify that is enabled in their settings. Periodically checking the "Locked Folder" (which does not back up to the cloud) and maintaining a secondary backup on a physical hard drive or another cloud service are recommended best practices for digital preservation.
For Google One subscribers or files recently lost from Google Drive (which sometimes syncs with Photos), contacting Google Support directly may occasionally yield results if the deletion was very recent. Proactive Protection: Preventing Future Loss how-to-recover-deleted-photos-from-google-photos
If the photo was stored locally on an Android device, third-party data recovery software might be able to scan the phone's internal storage for fragments of the file before they are overwritten. The best way to "recover" a photo is