Disney+/xfinity stream

I can't get the Xfinity Stream app to work yet either. The app is very finicky at best on other Android TV/PC devices too. At first they only supported it on Stand alone TV's it was baked into. I've heard it's designed to work ok on phones and tablets but not Android TV devices so it can't be used as an easy way to stream their service unless it's built into the TV. A Comcast Tech told me that. Somehow the software knows if it is on a phone or tablet and will work, but if it can tell it's on an Android TV device that can be physically connected to a TV then the software senses it and will give black screens and glitch out. Don't know it that BS or not but I can tell you this it works like a charm on my phone and iPad but it won't work on any Android TV/PC's I've ever tried to install it on.

I have not tried Disney+ yet

No, it's due to DRM and protections baked into Android Auto. Streaming / video services downloaded off the playstore won't work as is. Netflix for instance is using an old outdated and hacked build to avoid updates.