Anecdotally, the owner of the SV Seeker Youtube channel had their Youtube account terminated and lost all of their videos because they had uploaded some...adult content for a single viewer as a private video, which Youtube scanned and detected. "Private" just means "not discoverable."
TLDR Don't use Google storage in any capacity as a source of truth or sole copy, and encrypt if you don't want the data scanned, inspected, etc.
Google Drive scans files for copyright infringement - https://news.ycombinator.com/item?id=41049799 - July 2024
Google Gemini scans files on Google Drive without permission – can't be disabled - https://news.ycombinator.com/item?id=40962418 - July 2024
Google Drive adding spam folder, dark web scans for Gmail, more - https://9to5google.com/2023/05/10/google-drive-spam-view/ - May 10th, 2023
Google Scans Gmail and Drive for Cartoons of Child Sexual Abuse - https://news.ycombinator.com/item?id=29638263 - December 2021