MacOS Photos App - Not downloading ALL photos from iCloud in original quality?

Recently, I made the decision to pull back on my 4TB of iCloud photos storage. In preparation, I synced my Mac Mini's Photos app with iCloud with the intent of shutting off iCloud photo backup and going back to physically connecting my phone to my Mac to back up photos locally.

Even though the Photos app says it is synced with iCloud, I find that when I click on a photo, I still get a "circle" in the lower right-hand corner indicating that the photo is loading. It is also blurry for 4-10 seconds before snapping into focus.

To me, this seems to indicate that it is still pulling the photo from iCloud. I am afraid to turn off iCloud sync on my Mac because it says that all unsynced photos (low-res) will be deleted from my Mac.

Any ideas?