Two weeks ago I made a complete game jam game on my phone connected to a 1080p screen, keyboard and mouse. With a small fan nearby it didn’t even thermal throttle when compiling 
So, to clear any confusion, it works and has worked for many months now - IIRC the first time it worked for me was almost exactly a year ago (and when it doesn’t work, usually it’s a matter of changing the USB-C adapter/hub as some can be capricious).