mkirk76 wrote: …I’m using iCloud with “download originals” turned on. I back up my MacBook to a SSD. I don’t love the fact that if I accidentally delete a photo or video on another device, it does so everywhere.
Well, this is the purpose of iCloud-- it makes changes instantly available to all the connected devices. It is not intended as a backup service. Backups need to be kept on local drives, as it seems that you are doing. If you con't use iCloud to synchronize devices, you may not need it at all.
As such, I’d like to make a copy of my photos library on my MacBook, which will be backed up by Time Machine. I’ll just periodically replace the copy with a newer one as my library grows.
I use Time Machine to make a backup every day. Since my Mac is portable, I plug it in when I get home. (Actually, I have two Time Machine drives, an SSD and an HDD, and I go back and forth.)
In addition to that I periodically (monthly if I think about it) drag my Photos Libraries to an external drive. This is redundant, but I hard drive failure phobia.
I don't keep a backup on my MacBook, because if something (like theft, failed drive, or a truck running over it) happens to the Mac, then it would kill the backup as well.
You can make a copy by selecting the Library and choosing ⌘D (for duplicate,) or you can option-drag the Library to another folder on the Mac. You cannot put a Photos Library in the iCloud Drive Folder. However, a zip file of the Library can be put in iCloud Drive. You would remove it before you un-zip it.