If your device isn't recognized while in fastboot, you don't have the proper USB drivers installed. You can get them from the Google pixel support page

@jasonhopper I think you may have left the bracket in place, it needs to be removed with the old screen. I tried to alert people in my comment above:

"Also, the plastic bracket on the back of the screen usually is more willing to separate from the screen than from the phone chassis. I think this may lead to confusion for some people who may try to install the new screen over the old plastic. Some mention of this would be helpful."

After doing a few of these, using the fingerprint calibration tool is always needed. https://pixelrepair.withgoogle.com/udfps
I think it should be included in the final steps for completeness.

Also, the plastic bracket on the back of the screen usually is more willing to separate from the screen than from the phone chassis. I think this may lead to confusion for some people who may try to install the new screen over the old plastic. Some mention of this would be helpful.