Honestly, I always HATED dual-booting off one drive. It’s infuriating and Windows can and will fuck your boot loader. I always found it so much easier to just have two disks and select which one I wanted to boot from the quick-post boot menu, or hopefully have a grub that matches the windows drive. That way both disks stay agnostic of the boot partitions and partition types. When I was a runt in college I had a laptop with a drive tray back when those were a thing. Now I just run Windows in QEMU on my laptops.