Am I missing something? In CP2077's Manage Installation > Configure > Features, I have Cloud Saves unchecked, but apparently Galaxy is still syncing my saves up to the cloud. When the limit was first announced, I cleared out all my saves so that there weren't any more online and I disabled that option, but now I'm getting messages again about exceeding the cloud storage quota.

Is there another location where the setting needs to be turned off, or is Galaxy just bugged?

GoG Galaxy is a mess like any other game client. However, Galaxy is not a requirement, unlike every other game client.

Try running Cyberpunk 2077 directly from the main .exe and see if you get the same error then.
It's located under:
Cyberpunk 2077\bin\x64

I'll give that a shot, thank you.