Have you considered writing a guide on how you do this and what changes you make? I also own a Pixel, but kept running into problems when I tried to compile Android, eventually making me give up.

There's great work around from many people. See e.g.: https://github.com/dan-v/rattlesnakeos-stack

That's a whole toolset to compile your AOSP in AWS and then build your own over-the-air updates.