Reading the linked articles suggests that this is not possible, but Apple did acknowledge that the full-disk access grants you access to other apps (until the most recent update)

Typical "leopards ate my face" moment. You give AI (from Meta, nonetheless) full-disk access and then complain that—wow—it really meant FULL.

In a perfect world where you got nothing to hide, where companies don't sell your data and there are no hackers, even I would love to just hand all my data to Muse and have it be my trusted assistant. People who think we live in such a world are already doing that, evidently.