Hey there, I have this EXACT same problem.do you get that error in steamVR home too? I don't. When I go to launch a game all I see is that loading thing and that's when steamVR says mismatching GPU. the reason this confuses me is that the monitor is hooked up to the iGPU and so is the HDMI port on the monitor. As for the blank screen issue, I have that issue as well. I tried it on a cheap Chinese usb c to hdmi as well as a lenovo usb c to hdmi (I guess they're both chinese but whatever.) I did a little research and I think I read somewhere about a possible HDPC issue, but haven't had success so far. A quick note is there are two types of cables. Passive and active. Passive cables don't have any smarts in them and just display what the other end gives it. These are always bi-directional Active cables do an electrical conversion on the cable and are usually uni-directional