Hello Guy Glikson,
Thank you for posting in Microsoft Community forum.
Based on the description above, I understand you want to create a local group (WinRMRemoteWMIUsers_) on 2019 Domain Controller.
Based on my knowledge, when a server is promoted to a Domain Controller, we cannot open/access local users and groups console and we can not manage local users and groups.
Here is a similar thread that want to create a local account on domain controller.
[c1de-092c-647-5891] (microsoft.com)
You may need to try to find the other solution to resolve the function on the device.
I hope the information above is helpful.
If you have any question or concern, please feel free to let us know.
Best Regards,
Daisy Zhou