I've always thought it was exceptionally clear that Microsoft emphatically does not want you to dualboot.

That's why we got secure boot and why windows absolutely clobbers any other bootloaders during install, updates, and random points in between. It's why we have WSL.

I'll bet good money that Microsoft never even considers what you propose. It's antithetical to the mission of "lock all possible users into ad revinue streams". Microsoft won't get their windows ad impressions if they allow you to use a different OS on the hardware you own.

I'll be pissed if they broke my Ubuntu instance ...again under the guise of security.