Purge synced documents from iCloud Drive I'm using iCloud Drive to sync my Desktop and Documents folders to iCloud.

In theory this is good, but it's finished uploading every single file, and the files still take space on my HD. It doesn't seem that macOS makes space when needed, as when I try creating a large file with mkfile or try to copy a bigger file through the Finder it fails saying there's no space left.

I know that if I'm sure all files are syncronized I can switch iCloud Drive off and back on to free up space, but is this really the official and/or best way to free up space after syncing is finished?

I assume a "Free up space" button would be an obvious addition to the UI? What's the best way to remove files that are already synced?

After years, iCloud still seems like a half-baked product to me.
It works as intended, I’m afraid. “Your Mac keeps all of your recent files on your computer, but keeps your older ones only in iCloud, ready for you to download when you need them again”, Apple says. So as long as you still have enough free space on your hard disk the files will stay there.

Please see Apple’s article Free up storage space on your Mac for tips on how to free up more space on the Mac using iCloud.