well you see that's the problem, windows doesn't believe in this cute little thing called following standard, so sometimes it just fucking yeets that shit, taking the bootloader with it, because keep in mind, when you dual boot on the same drive. You usually end up using grub to dualboot between linux and windows, which windows doesn't like.

And as for installs, some updates are basically installs, so who knows what the fuck kinda bullshit windows will be doing then. And like i said, if you ever do a clean install on a system with other disks, you better hope you get lucky.