Managing how much iCloud storage space is used on Mac

I am using MacOS Mojave and I just upgraded my iCloud space to 2TB with the intention of moving all of my files that I store on other cloud services (both Box and Dropbox) over to iCloud. Since I've moved my stuff over though (about 800GB), there has been no way to limit the storage usage on my mac (500GB SSD), so I keep getting the error message that I've run out of space. Other than "optimize storage," which causes the mac to keep only about 10GB free at any given time, I can't find out how to have iCloud use less space on my computer, so that I can free up more space (at least 100GB at a time), which I need for the audio and video work that I do relatively frequently. There's no "selective sync" option, to my knowledge (like both Box and Dropbox offer), and there is no way to ask iCloud to use less space than almost the entire hard drive on my mac. Other than "delete files," which is primarily what I've found in the other threads, are there any suggestions for how to fix this issue? Any future product updates coming down the pipeline with something like this?