> Last time I checked, RDP wasn't able to use your GPU at all unless you had a very specific, no-longer-maintained version of Windows 10 Pro
Not sure where you got that idea. RDP has been able to use the GPU for both encoding and the apps since Windows 7 era and both certainly still work on the current version of Windows 10. The main limitation I've run into is it's still limited to 30 FPS though.
During the Windows 7 era it required Enterprise or Server, during the Windows 10 era it requires Pro, Enterprise, or Server (or that Pro for Workstations version you mention). Remember you have to actually enable it though, it's not configured by default.
Perhaps you're thinking of the deprecation of the RemoteFX guest vGPU for the Hyper-V role?
Not sure where you got that idea. RDP has been able to use the GPU for both encoding and the apps since Windows 7 era and both certainly still work on the current version of Windows 10. The main limitation I've run into is it's still limited to 30 FPS though.