Hi there,
I have built a similar bot working on Amazon and Walmart eCommerce websites which has all features you listed out in the project description. It is able to register new account, signin and resolve captcha, auto search, add items to cart and checkout items(including auto fill shipping address, credit card,...)...
Basically, it is a winform application which embed chrome browser to simulate any action as the human does. It runs fast and perfect. I will show you how my bot working when we have a conversation. Looking forward your response as soon as possible!
Thanks,
Hao