I thought the implication of "disabling" OneDrive was exactly that.

One drive creates a local directory that you can save files in, and all the files in that directory are synced to cloud storage. You can free up storage by removing it locally and only storing it on the cloud, and you can pull files from the cloud to use locally, so you can access the same files from any device you log into. But you dont have to save your files there where they are synced. You can save them in normal local directories instead.

Disabling one drive disables the sync functionality, so saving files in the one drive directory are only stored locally and you cant pull or even see non-local files or updates to those files from the cloud. But that doesn't disable the login requirement to access that directory because it is still tied to a specific Microsoft account, not the local device account. So one could use the one drive directory as a password protected directory to prevent access from other users (though there are much better ways to do that). But if that is not the goal, there is no reason to log in to one drive or its directory at all. In fact, it could be uninstalled altogether and then everything will just be a normal directory.

This guy doesn't want to use it at all and it keeps throwing errors anyway.

Then he can uninstall it, unless his work computer admits dont allow it. Dont get me wrong, it was exhibiting fucky behavior, and Microsoft is very often "helpful" in ways most antithetical to the word, but the fix for software you dont use is always the same. Uninstall.