Photos synched to iCloud but images remain on mac taking up memory
I have low memory on my Macbook (<3 GB out of 128 GB). I've run through the memory management task a number of times but I can't free up any more space except for Photos. I have a my Photos synced in iCloud (Photos -> Preferences -> iCloud Photos (checked) -> Optimize Mac Storage (radio button selected)). Instead of freeing up space, Photos is now downloading more from the cloud (13.8 GB is now over 20 GB). I've been in the forums and all over the internet trying to figure out why Photos is not doing what it's supposed to and moving all images to the cloud. I need forum help to get this to sync properly and maybe find the folder where all of these ghost images are and manually delete them? Kill Photos and reinstall? Reinstall the OS from scratch and re-sync my AppleID?
OS Mojave 10.14.5
iCloud storage enabled with 116 GB of 200 GB used (and it's $3 per month for this frustration)
MacBook Pro 13", macOS 10.14