You don't have to pick a photo category, or manually pick photos, any more.
https://www.cnet.com/tech/services-and-software/ios-17-1-lets-you-pick-an-album-for-your-photo-shuffle-lock-screen/?utm_source=dlvr.it&utm_medium=blogger#ftag=CAD590a51e
https://www.cnet.com/tech/services-and-software/ios-17-1-lets-you-pick-an-album-for-your-photo-shuffle-lock-screen/?utm_source=dlvr.it&utm_medium=blogger#ftag=CAD590a51e