This quote from your article does nail the problem on the head though.
It nails a different problem on the head.
You don’t have to convince the US government to allow you access to classified information, you just have to convince a lawyer that their (possibly non-US) client won’t be liable in case you are lying.
The best option would be to have a “regular” client that keeps a local copy in sync with the cloud instead of a mount.
BTW: IDK what cloud storage you are using, but IIRC some show files that are not available locally (ie. only the most recent files are downloaded locally - the older stuff is downloaded on request).
Alternatively, you could hack something together running unison locally in the guest to sync the cloud folder to a shared one… you’ll have two copies of the data though.