nostr:npub1rnjwv8da8gxyg5xdundvwcg9r489cnuaa842pzes005ezq9q0jvsgrvtmy
ChromeOS.
It's Linux.
I'm not a fan of Google, but let's not get into the evil Google stuff. It's your most likely choice if you want to get someone off of Windows and not be their personal tech support team. A good number probably use Chrome and Google services (on Windows) at this point anyway.