Photos
How can I remove duplicates in my photos without doing it one at a time?
iPad, iPadOS 14
You would have to upgrade your iPad to iOS 16: Then yiu can use the built-in duplicate detection.
See: Merge duplicate photos and videos on iPad – Apple Support (UK)
You can select multiple groups of duplicates to combine them at once. But frankly, I would not do that. Photos is also showing similar photos as duplicates, not just exact duplicates. For similar photos Iwant to be the judge of it, which version will be kept, as it is a matter of artistic taste.