Thank you very much for your feedback.
We might consider the localhost connection on Windows viewer app in the future, but not anytime soon.
We cannot prioritize it at the moment as we are very busy with higher priority tasks.
For now, you can only use HTML5 viewer for localhost connection.
By the way, if we understood your reasoning correctly, does our spacedesk driver worked in a remote session?
Did you not encounter any display driver issue?