Creating a universal bootable Windows Installation USB drive on Mac OS is straightforward. The only pitfall is you have to format your drive as FAT32 to maximize compatibility, but then you have to split your .WIM file to smaller chunks than 4GB so that it does not get corrupted. Fear not, I will guide you through the process. Big thanks to this comment by m13253 for most of the heavy-lifting of this Gist.
Here are the steps (assume your FAT32 formatted USB drive is mounted on /Volumes/USB
and your ISO is named something like Win10_1903_V1_Germal_x64.iso
):
❗Preparation:❗ Format your USB drive as FAT32 using Disk Utility on Mac OS!