[formerly_proven]

Didn’t Microsoft do this already? I recall a Windows update blacklisting vulnerable Linux bootloaders in UEFI.

KB5012170

So if they don’t blacklist vulnerable ntldrs, it’d be clear evidence of unequal treatment.

[wkat4242]

I bet they are a lot more inclined to blacklist old Linux bootloaders than Windows ones, precisely because of this backup restore thing that the OP mentioned. They'll get the support burden if nothing else.