@wertor I know it’s been a long time but have not found enough time to work on this earlier. We now have a first version of init.xz capable of capturing and deploying a Windows 10 2004 UEFI/GPT install with recovery partition at the end. Would you give that a try.
Please be aware this is still in kind of a pre-release phase. Make sure you have a backup of your original image as well as the machine you pull the master from, just in case!!