I’m assuming the EU speeds up the uncoupling cause of some of this.

I think anybody who has been paying attention has assumed for at least 20 years that all of Microsoft’s shit is backdoored anyway. I mean, the original Snowden revelations made that abundantly clear if it wasn’t before then.

Businesses use Microsoft because they figure if it’s backdoored it doesn’t matter and won’t affect them (because they aren’t terrorists or child pornographers or whatever, and they’d comply with a subpoena regardless of if Bitlocker is backdoored or not) and individuals who care about security and privacy put their shit on a Veracrypt drive somewhere else.

It's not an actual backdoor. An attacker found a way to exploit Windows after booting it up in this recovery mode. The security of files on the device depends on it being impossible for Windows to be pwned by an attacker on any surface exposed before the user is unlocked.

This is why operating systems like GrapheneOS disable the USB port on the initial boot to limit the attack surface that an attacker has.

As far as I can tell, there's no concrete evidence that it is actually an intentional "backdoor."

I don’t think anyone is using Windows for privacy, so I’d say nobody will care.