Syncing iCloud photos to all devices is causing problems

I’m having trouble with iCloud uncontrollably syncing my entire photo library to all devices. My Apple ID is connected to 4 separate Apple devices that I use for different work-related purposes. I’ve just upgraded my iCloud storage, thinking it would only UPLOAD photos from all my devices to iCloud. Instead it’s DOWNLOADED thousands of photos to each of my devices and created a horrible muddle by mixing all my photo libraries from different devices together. Is there any way to detangle them and automatically unsync everything that doesn’t belong on a particular device? I tried turning off iCloud on my phone but the photos that synced from other devices didn’t go away even though I said “remove photos”. Any help would be appreciated! Thanks in advance.