I've just swapped my OS drive for another drive. I installed W11 on the second NVMe drive, confirmed it all worked, then wiped the old drive. Now the computer won't boot even though one of the nVME SSDs has Windows 11. The disk has no unpartitioned space.

Updated: The new drive has no EFI / boot partition. I'd appreciate suggestions how to create one, which will likely involve repartitioning the disk. For now I'm doing a backup of my disk with Macrium so that if things go wrong I can likely recover it.

Updated again: following this reddit post.