https://support.google.com/pixelphone/thread/100761384/factory-reset-with-a-broken-screen?hl=en
With your phone’s buttons (advanced) If you can’t reset from Settings or you can’t use your screen, try a reset with your phone’s buttons. 1 If your phone is on, press and hold the Power button to turn it off. 2 Press and hold the Volume Down button and Power button at the same time for 10-15 seconds. If you hold the buttons for too long, the phone restarts. If this happens, try again from step 1. 3 Use the volume buttons to change the menu options until "Recovery Mode" is displayed on screen. To select, press the Power button once. 4 On your screen, “No command” is displayed. Press and hold the Power button. While you hold Power, press the Volume Up button and let go of both buttons quickly. 5 Android Recovery options should be displayed. With the volume buttons, scroll to "Wipe data/factory reset" and press the Power button. 6 With the volume buttons, scroll to "Factory data reset" and press the Power button. 7 Factory reset should start. At the bottom of your screen, when the reset is finished, "Data wipe complete" is displayed. 8 With the volume buttons, scroll to "Reboot system now" and press the Power button. 9 To set up your Pixel, after the phone completes the OS install, tap Start. 10 Follow the on-screen instructions to set up your phone and restore your backed-up data. Learn how to back up or restore data.
https://www.youtube.com/watch?v=dyTztc71WwM 2nd half of the video may help you to reset the phone.