My memory is that it was an ARM based laptop. This story seems to confirm that: https://arstechnica.com/gadgets/2022/08/linus-torvalds-uses-an-arm-powered-m2-macbook-air-to-release-latest-linux-kernel/

I think it was the Asahi district.

You absolutely can roll back to previous versions using the steps in those links. I believe it has a 30 day limit, but that is pretty good for a consumer product.

OneDrive does offer restoration of individual file versions or even the entire OneDrive contents (for things like ransomware attacks). Details are here

I think OneDrive is a pretty good (but paid) backup utility especially for non-technical people. There are a lot of things that I could nitpick on, but for some of the older people (octogenarians) that I am the family support for, I set it up and anytime I interact with their computer I click on OneDrive to ensure it is replicating. I very occasionally have seen a single file not replicating, but never have I seen it fail completely. These people previous had NO backups of any kind.

I use it myself as an additional backup location, but not in the way most people would.