Etcher was stuck on my Mac and can not complete the burning process
The above advice is very out of date and no longer applicable to your situation. You are experiencing issues due to how Microsoft changed their installation methods as of Windows 10 v 1803. The WIM files are larger than what the FAT filesystem supports. The Microsoft tool is already aware and works magic when writing an iso to let this happen. The developer of Rufus is also aware and was able to hack together a solution that requires disabling secure boot while installing.
Thanks, Microsoft…
Anyways, Etcher (or any other software/terminal DD on Mac) follows protocols and errors out while trying to write a file larger than the file system allows. Also, changes to Bootcamp removed writing to an external USB drive and now sets up Bootcamp using a RAM disk in a temporary drive partition. You will not get this to work with mac native tools.
Your best solution is to either boot to Linux and use tools available there to write the iso to USB, or load a VM (VirtualBox is free - but a parallels trial would work much better) with Windows 10 and use that to create a USB drive with Rufus or the actual Microsoft Media Creation tool. That is what I use for work and it has never failed (the VM that is - both Rufus and WMCT should work fine).
Follow that advice and you’ll be up and running. Or download one of the original versions of Windows 10 (assuming you can find one from a trusted source), use etcher with that, then upgraded to the latest 1909 or whatever version you are looking for.
Good luck!