"I’d make the exception for Google Drive, OneDrive and whatever the AWS one is."
No - no exceptions.
We must, as sophisticated 21st century actors, insist that providers (especially providers of critical services) have financial interests that align with our own interests.
I don't care how big the parent is or how much money they have to burn - if it makes financial sense to keep you from storing your backups you need to go elsewhere.
You’re missing the point. Those companies are providing extremely profitable services, of which data storage is a part. Office and Workspace are lines of business with 50-60% margins.
Non-nerds are going to screw up backups without good UI. If you want to pay by the drink, like I said, use the hyperscalers.