MacBook M4 Pro Bootcamp and Win 10

There is no Boot Camp on M-series Macs. It doesn't exist and you can't run Windows natively on Apple Silicon at all.

The only way you can run Windows on Apple Silicon is Windows 11 ARM in Parallels Desktop (or another VM product that supports Windows 11 ARM, but Parallels seems to still be the best for support).

Windows keys should transfer between WIndows 10 and 11...but the steps you will need to go through to "migrate" from a Windows 10 Boot Camp install to a WIndows 11 ARM VM install probably needs additional help from Windows Tech Support, to be honest.

You’re moving from Microsoft Windows 10 on x86-64 Intel processors, to Windows 11 on ARM for Arm64 processors.

Both upgrading from Windows 10 to Windows 11 and migrating from x86-64 to Arm64 architectures add to the considerations here.

Here is what Microsoft supports with Apple silicon Arm64 processors:

https://support.microsoft.com/en-us/windows/options-for-using-windows-11-with-mac-computers-with-apple-m1-m2-and-m3-chips-cd15fd62-9b34-4b78-b0bc-121baa3c568c

As correctly stated in the reply above, Microsoft expects you to be using a virtual machine (e.g. Parallels) and not native boot (e.g. Boot Camp). Or Microsoft expects you to use Windows hosted on Azure or otherwise, of course.

Windows 11 on ARM includes an emulator for running Windows apps built for x86-64, as well.

Windows 10 or Windows 11 built for x86-64 will not run on Apple silicon. Not without emulating the whole thing, and you probably don’t want the effort and overhead in emulating all of Windows.