Upgrade Windows 10 Pro to Windows 10 Pro for Workstations  

Brink said:

I just tested, and you are correct. There's not a "Windows 10 Pro for Workstations" option available anymore in Windows Setup from an ISO from the Media Creation Tool.
As a workaround if using an ISO from the Media Creation Tool, it looks like you will have to install Windows 10 Pro, and then upgrade from Pro to Pro for Workstations afterwards.

I take it that you have a VM to test this out. Can you redownload Windows 10 from the same page you get the Media creation tool. But first you have to emulate the page to make it think that you are downloading from an iPad Pro. Make sure to refresh the page after turning on iPad pro emulation in Developer settings (F12). Once this is done, it will give you an ISO download choice that has a Wim file instead of an ESD file.
New installation of Windows Pro for Workstations on new SDD from USB - Microsoft Community

Download Windows 10 ISO File | Tutorials (tenforums.com)

Brink said:

Just tested. Using the ISO from option 3 does allow you to select Windows 10 Pro for Workstations during a clean install.

Perfect, that fixes the problem and answers everyone's questions. Thanks a bunch