I would be surprised if there is such an "do everything' automated app. It may come down to a workflow process you feel comfortable with. While my largest job was my mother's trays and trays of slides, I have done stacks of photos using only the software that came with the scanner, usually in 'professional mode' which gave me more control than the more automated roles. While I use a flatbed, perhaps a dedicated (expensive) photo scanner would come closest where you feed prints in individually.
Using a flatbed, if slide capable will have a holder for around 4 slides which will automatically scan individually. Prints, sort for consistent size and can usually lay 3 of 4x6 on platen and orientation doesn't matter as can later flip in Photoshop. Establish the 4x6 scan area (or whatever size for the pile you are working on), scan, then simply move that 4x6 block to the next photo on the preview screen, repeat and will remember that scan area as you load the next 3 until finished that pile of photos. Then start on your next size, 5x7 or 3 1/2 x 5, etc
When finished, still would want to take a final step in Photoshop, correcting color shift over time, dust or print damage repair, tonal adjustment, etc.
Then finally, after all that work, make a backup! I also with my mother's slides made additional copies which gave to my mother (display on TV rather than haul out projector), as well as for my brother and sisters.
