Install Windows on Mac Without Bootcamp
Bootcamp just packages some drivers and saves you time from learning how to manage the boot process, there’s zero requirement to use it. The only hard step is on macs with T2 chips, you have to disable secure boot, so watch out for that.

I really like BootRunner since it saves me far more time than the cost to pay for my seat, but I also really like to keep dual booting. See if it saves you time before paying for it. For me the support for third party graphics cards was very appreciated.


https://twocanoes.com/products/mac/boot-runner/


There is no one more knowledgeable that David Anderson and his posts are master classes in how to work with storage on Mac hardware. How to install Windows 10 into a 2013 iMac without using the Boot Camp Assistant, USB flash drive or third party tools?

I would put in a smaller drive temporarily so you can vet his instructions on 512 block size if you can’t wait for him or someone with his skill to do the math if you can’t figure out which items in his recipe need an adjustment.