Finding a micro USB to USB-c OTG adapter that actually works is difficult for some reason. This cable from Fiio does just that. I was able to successfully play music from OnePlus6 on Schiit Modi 3 after enabling USB OTG in settings. I only wish this cable was longer, under six inches overall. The lack of length prevents me from carrying the phone anywhere other than directly on my DAC and thus out of reach.