X11 forwarding for the Desktop app seems like it would be easier than in iOS.
I am creating a separate issue here in the hope that it could be implemented in the desktop app more rapidly. The iOS improvement suggestion has been there since 2014.
Alex Sanderson commented
An X windows implementation is unnecessary in this case as many already exist.
It could be as simple as just forwarding port 6000 on remote to localhost:6000 if a box is ticked.