There is photo scanning/camera software out there on phones that detects edges of documents/regions, then crops and deskews the image. My Xiaomi Redmi Turbo 3's

There is photo scanning/camera software out there on phones that detects edges of documents/regions, then crops and deskews the image. My Xiaomi Redmi Turbo 3's camera app has a "document" mode that does that. I also know of other software (for example, Paperless Mobile — though it is not its primary feature) that does that. I think this would be an improvement to the OP's process: Print a thick black rectangle sized such that the contour's inner edge is slightly larger than the CD. Use the phone to take a picture and deskew it - the scanner should "catch" on the inner contour. Repeat with all other CDs. Finally, load the images onto the computer and run batch processing on them using your raster image editor to trim whitespace. This way, you'd keep manual labour to a minimum.