Hi,
What is the detailed Windows OS version of the Hyper V host?
As far as I know,
Windows 10 1809 removed the VMRemoteFX3D adapter from the Hyper-V GUI, but you can still add it via Powershell, please try if it could work for you:
Add-VMRemoteFx3dVideoAdapter -VMName [vm_name]
Thanks for your time!
Best Regards,
Anne