Unity 2019 + GoogleVR SDK Android - laggy framerate

I have a GoogleVR/Cardboard app that downloads and displays 360 video. It works very smoothly on iOS, but on Android, it's very laggy, so it is unwatchable. I've looked at the profiler, and it seems that VSync is taking most of the frame. In the Quality settings, it has it set to "Don't Sync", so I'm wondering if there is a problem there. Here's what the profiler looks like:

The scene is quite simple. It's a simple inverted sphere with a texture for a background, and a few UI buttons for downloading the videos for viewing. Even after downloading the 4K stereo videos and watching them, the FPS is still the same. Anyone run into this?

Thanks!