Q: Signing out of iCloud during upload

Skip below for QUESTION

I have a Macbook Pro runnning Sierra 10.12. In my Photos Library, I have 28,111 photos.

On iCloud.com, I have 18,796 photos and 416 videos (19,212).

The thousands "stuck" are easily seen...

These have been stuck for over a week now. Wifi connection is strong. Computer has been reset many times. On other discussions, it advised to clear the Recently Deleted folder and Trash can, which I did and it seem like that "unclogged" it a little bit.

My next attempt (per other discussions) is to sign out of iCloud/turn off iCloud Library and sign back in. When I start that process however I get the following window:

..and when I select "Turn Off," I get this:

QUESTION:

If I select "Remove from Mac," will those 11k photos be deleted from my computer or simply removed from the sync process? Obviously I don't want to lose 11k photos but I would like for iCloud and my Photos Library to be synced. What are my options to proceed?

Notes:

-Tried resetting my Mac

-Cleared Recently Deleted Folder and Trash Can

-Have 884gb of storage available on iCloud

Thank you.