Using iCloud for multiple devices
I want to increase my iCloud storage limit so that I can share with my wife for her iPhone. I currently use a Mac, iPhone and iPad. Currently I do not use iCloud for photos and each device has a unique set of photos saved on the device. I am concerned that if I elect to use iCloud for photos on each device that iCloud will consolidate all photos and I will lose ability to identify and restore just the photos currently restored on each device. Also, if I use iCloud for photos, will I still have all my photos stored on my device as well as on iCloud or once I go to iCloud will all my photos be stored only on iCloud?
Thanks for any input.
iMac 27", macOS 10.15