While I agree with your assertion in theory, I cannot agree that windows doesn’t mess with grub. I have had 5 different issues with grub being overwritten, 1 was because windows and Linux were on the same drive, but the other 4 was simply because I launched windows through grub.
My advice for people dual booting is to never launch windows through grub and instead change your boot order in bios, this has made all of my boot related issues go away.
Thank you, I was aware of this, but I believe you are mistaken in your last sentence because Linux has always been the second one to be installed for me and the issue still crops up when I forget to heed my own advice