I don't understand what's your suggested setup is, could you expand on that?

So you have a Linux desktop that runs a Windows VM that runs multiple things at once: the app you want to run; an RDP server that is configured via 1 of those 2 tools to stream just the app's window instead of the whole Windows desktop; and on top of it you run the other 1 of those 2 tools you linked to wrap the RDP server's stream into a web server, so that instead of running an RDP client on your Linux host to access the Windows-hosted app you could simply use the browser?

Is that your suggested setup?

If yes - then it won't fit resource-demanding gaming, as for such games you'd need to pass your GPU to the Windows VM and thus your host Linux loses a GPU, so you need a 2-GPU setup for that to work comfortably.