I would happily trust microsoft's corporate cloud - and the certification and insurance that presumably comes with it. Even the public-facing OneDrive I'd consider better than many of the alternatives (such as Dropbox) - MS has some pretty good security engineers.

Then you shouldn't trust Slack either. You're kidding yourself otherwise.

but you would trust slack with your data ? Also Microsoft has on prem version so you don't have to trust anyone

your c