iCloud Drive is never finished syncing

Additionally, I consistently get the "syncing paused because you're out of space" error, and a warning that system memory has run out. I simply don't understand how these core functions of the OS can be so broken at this point.

Thanks. Yes of course I have tried rebooting, lol. It usually does eventually stop syncing and the problem will "go away" for a while, but it always happens again sooner or later and makes my machine pretty much unusable for 8-12 hours while it tries to download everything. I just want to understand what causes this behavior so I can avoid triggering it.

I was not aware of the EtreCheck tool, thanks for the recommendation. In my case it was not helpful as it did not find any issues.

I'm manually deleting them because iCloud won't do it. Which is the entire premise of the post.

To your point that "iCloud Drive may not be what I need" - you're telling me that normal users that have multi-terabyte hard drives and want access to those files on their iPhone, iPad, etc. are expected to have enough storage on every single device to accommodate the entire contents of their drive, should iCloud spontaneously decide it wants to download everything? Be serious - that is not the intended use of iCloud Drive at all. The very existence of the "optimize storage" option explicitly demonstrates that the service is intended to hold more files than can physically fit on a hard disk.