Hidden album photos missing after iOS 18.1 update
Many have posted that they "lost" their Hidden Photos album after the 18.1.1 upgrade: They option to view is gone from the Photos>Utilities menu.
I finally remembered what happened and fixed mine very simply. Go to Settings>Apps>Photos then scroll down and you will find a "Show Hidden Album" toggle, simply turn it On.
I guess they moved this option to a more sensible location under the Apps>Photos menu and changed the default to OFF.