I've also tried moonlight (which is an nvidia gamestream implementation), which seems to have performance but the client wasn't very usable for this usecase.
Still great for general productivity type stuff though!
RDP/termsrv by design create a new session for incoming connections. However, with Windows Virtual Desktop (WVD), Windows Containers and Windows AppGuard, we definitely have a way of launching remote applications in an existing session.
Have you perhaps looked at WVD or RemoteApp? If you'd like to talk more professionally, you can email me at {first_name}.{last_name}@microsoft.com (my name is available on github.com/zeusk).
I am able to RDP freely onto desktops with rtx 2070/gtx 960 cards no problem.
Is this more something specific involving some degraded performance/reduction in features?
The issue seemed to be switching between remote and local access, i.e using the machine locally, then from remote, then coming back to local. It would usually survive a couple of cycles of this then just be a black screen after login. Once in that state tricks to reboot the graphics driver did not work and reporting in speed working too, though the rest of the machine was up as services like IIS and file shares kept responding just fine.
My hacky solution is to run VM for most day-to-day work on that machine and remote to that, only using the bare metal when I need the fancy gfx card or otherwise the little bit of extra unpf gained by not having a virtualization layer in the mix.
I really dislike our reliance on TeamViewer, especially now in covid times where were relying even more on remote access.