The fix for this used to be that you'd just install the systems on different physical drives. Changing their boot order in Bios during install so Windows is going on the primary/boot disk. You then swap them back and update grub on your Linux side. When you use grub to boot windows it temporarily re-maps the drives before booting so that windows thinks it's the only OS on the primary drive and is happy without touching your grub setup on the 'real' primary drive.