Unless there's a "database failure" that would resurface screenshots from your PC on Microsoft's cloud, or anything like that. I mean, its too many lines of code, what if something happened and oops, the local data was uploaded to your Onedrive, my bad, keep using our products, this will never happen again we swear.

The only way to be sure is not having it at all. Remember the CSAM filter Apple wanted to force on iOS? This is as bad as that.