I'm running a 2018 MacBook Pro 15" with Mojave. I recently purchased a StarTech USB-C to VGA adapter, model CDP2VGA. Unfortunately, the Mac does not seem to detect the adapter. I know the adapter works because it is detected on my phone with USB-C and outputs correctly to the display.
There doesn't seem to be any detection with the Mac. I've tried restarting, didn't work. There are no drivers to install. However, occasionally, the Retina display flickers when the adapter is plugged in, suggesting that something is there.