Your post a couple years ago, “The Ins and Outs of Non-Destructive Editing” (https://tidbits.com/2019/06/14/the-ins-and-outs-of-non-destructive-editing-in-photos-for-mac-and-ios/) has been very helpful in understanding the limitations presented by Photos, both on Mac OS and iPad OS. I’m curious if any of the limitations you described in this post have changed over the last couple years or if you see anything recently announced for iPad OS 15 that could change them?
The built-in Photos app now supports RAW images. However, all of the other behaviors are unchanged. I don’t believe anything has changed in iOS 15, but I haven’t looked into it deeply yet.