Yes, you can install Windows 8, 8.1 or 10 in UEFI mode by choosing EFI boot in boot picker menu.

Windows 11 is also supported if you create a special patched USB stick.

Just press Option key (on Mac keyboard) or ALT key (on Windows keyboard) on boot to see all bootable partitions.

Make sure that your Windows disk/partition is formatted in GPT format, because installation on MBR partitions is not possible in UEFI mode.

After a successful Windows installation you can use Bridgadier tool to download all necessary Apple BootCamp drivers. Download and run brigadier.exe: https://github.com/timsutton/brigadier/releases

For Windows 10 you need to use a following command in command prompt to get the latest drivers.

Press Command + R or Windows logo + R then type cmd to run Command prompt.

Then type:

brigadier.exe -m iMacPro1,1

to download drivers package.

We recommend installing 7-Zip before installation of this tool: https://www.7-zip.org which is needed by bridgadier tool to unpack all the files.

Finally run Apple BootCamp drivers installer by runnning a follwing commands in the terminal:

cd BootCamp-(press TAB)\BootCamp\Drivers\Apple

msiexec /i BootCamp.msi

Check if Windows is really installed in UEFI mode by pressing Command key + R (on Mac keyboard) or Windows logo key + R (on Windows keyboard).  Type msinfo32 in the Open: field and press OK button. BIOS mode should show UEFI. Otherwise there will be Legacy in this line.