It seems that Sidequest is running on your Pixelbook and tries to install stuff on it. I assume that you have your Quest set up to be in developer mode (and your Oculus account is also dev). If you connect Quest to Pixelbook, is there any notification popping up? Or can you try running from a commandline "adb devices -l" (or use "Run ADB command" in Sidequest to run this). This should list all connected devices. If Quest is there, you have to change the target device in Sidequest - although I don't see any icon or setting to do that :(
If you have Discord, you may ask for help at #support-general at Sidequest server (https://discord.gg/yfa9hT).