I doubt that Microsoft has a kill switch. Though through automatic updates they still have pretty strong sabotage capabilities.
But the OS is not where Microsofts power lies. Its in exchange (almost everywhere cloud managed, including for many governments) and SharePoint, with a small amount of teams, where Microsoft is truly a scary prospect for sovereignty.
The kill switch is M365 account management. You take that offline, many SME’s and local governments just stop working. At least for a while.
> pretty strong sabotage capabilities
Via updates they can install and run anything they want ... aka 'kill switch'.
They absolutely have. They force upgrade computers to Windows 11, which then won't boot, because the system doesn't actually support it. I guess they also have a smoother way to achieve that. They are also cases where an update broke the booting process, so the bitlocker key was lost. Everything is encrypted with it by default, and the only copy sits on a MS server connected with you MS account. Guess what happens when they say sorry, we can't just give you that key...
They have the kill switch, it is called a "cloud account". Nowadays you need a valid cloud (MS-controlled) account to log into your computer.