Finally got my Pixel 3 XL battery that I ordered off of Amazon. I actually haven't had an issue with battery life with the phone yet, but figured it would be handy to have for those days I'm out on vacation with my family and plan to take a million photos while out. It looks like it also does fast charging (photo shows "charging rapidly").
If interested, this is the one I got:
https://www.amazon.com/gp/product/B0...cUvbUpU6405082