When I built my new PC I also spent a couple of hours on it, because most of the old documented and simple solutions did not work.
When I had a big partition that could hold the image the system wouldn't want to boot from it. On the small Fat32 partition the image didn't fit.
I think in the end I had to create 2 paritions, a Fat32 and an ExFat one. Then I had most of the boot files on both, but the big windows image only on the ExFat one.
That actually works - when the installer can't find the big image on the original partition you can point it to the other one and the installation will continue.
When I built my new PC I also spent a couple of hours on it, because most of the old documented and simple solutions did not work.
When I had a big partition that could hold the image the system wouldn't want to boot from it. On the small Fat32 partition the image didn't fit.
I think in the end I had to create 2 paritions, a Fat32 and an ExFat one. Then I had most of the boot files on both, but the big windows image only on the ExFat one.
That actually works - when the installer can't find the big image on the original partition you can point it to the other one and the installation will continue.