I am using the Satechi USB-C HDMI adaptor below on my Google Pixelbook to connect it to my external screen via HDMI. It runs flawless and you can also connect USB devices to it. I use the Logitech mouse dongle and a Bluetooth keyboard additionally at the Pixelbook. I can then close the Pixelbook lid and run it controlled by an external mouse and keyboard on the external screen.
The color of the adapter matched perfectly with the Pixelbook.