I’m very sorry to hear about your experience. If you are using RAW Power with the Photo library, then all of your edits and ratings are preserved after deleting the app. That’s because the data is stored in the photo library. If you use the “Files” side of the app (integration with Files.app), then deletion will remove ratings and edits because those are stored as part of the app’s documents and those are deleted when the app is.
It sounds like the library is not loading in the app, which is very odd. Please email email@example.com because this will take a little back and forth to figure it out.