They are using Arch instead of ubuntu crap so I guess that’s good

You can disable the builtin display or just get rid of it physically

You’re kind of rude to assume that they are not sensible enough not to trust what ChatGPT says blindly. I also use LLMs but I check if everyhing is alright before I do anything it suggested me to. IMO, it’s okay to use LLMs if you can learn something from it. (but I can’t afford a server with a GPU, sadly)

Macbook Pro should work fine. Buy extra PCs if you it’s not enough for you. Also, I recommend buying a domain from a legit provider