Booting from a cloned Windows 10 installation I have Windows 10 Pro installed on a external flash drive, I tried to install Windows via bootcamp but it is required to have more free space. I succeeded to install Windows 10 with VirtualBox on a SanDisk 32 gb flash drive and boot into Windows 10. The drive capacity is too small so I bought a Kingston Kyson 64 gb USB 3.2 flash drive, but it will not work with Bootcamp.
If I fresh install Windows with VirtualBox, the installation process will stop around 40% and reboot to EFI interactive shell.
If I clone SanDisk &gt; Kingston from another Bootcamp machine, the clone drive will boot to Windows loading screen followed by BSOD.
If I clone SanDisk &gt; Kingston from the booted Windows 10 drive, the clone drive will boot to Windows loading screen followed by Startup blue screen.
If I clone sector-by-sector, the clone drive will boot with BSOD 0xc0000225, 0xc000000e, Missing / Damaged Winload.efi.
IMO, flash drives are not designed to endure the amounts of writes that would be performed by having an operating system installed on the drive.
There are many different mechanisms which can be referred to as having cloned. Since you have not explained how you cloned Windows 10, I will assume you are confident Windows 10 was correctly cloned. Windows does have the ability to detect when being cloned and if detected, can result in Windows 10 not booting properly. The general solution to this problem is to rebuild the BCD.

I realize this answer is vague, but this is only do to the lack on details in your question.