I wish I could upvote this more, as I've been blown away by the speed as well.

Also, the deep integration of Siri Shortcuts with iOS opens up so many possibilities for automation for this - maybe OP can help their mother with setting up one or the team at an Apple store could help (I've had some experience with making an appointment with them to help me with a shortcut I was building for Apple Health.)

But I also agree with some of the other commenters that just leveraging iCloud / Apple Photos out-of-the-box should suffice.