If I delete a photo on ICloud from both my photos and the 'recently deleted' folder, can it still be recovered?
Solution 1:
No. Apple only holds photos for limited time in deleted items. That is your chance to reconsider. You could open a case with support to confirm, but the place to get these is from local backups. iCloud isn’t a backup just like files on your devices aren’t a backup.
So sorry if this wasn’t your expected answer. It’s never good to lose data or learn you didn’t have backups.