Same here. Another dark pattern is they require the country code, they could have inferred it from my IP and auto populated it or had a list of countries via a dropdown instead they bury that the country code is required in a paragraph and disable the button if the phone number lacks it. At very least enable the button and pop up a error message if the country code is lacking. How many non technical users will give up with this form? I suspect many of them.
I don't think it's the case that your country code can be reliably inferred from your IP. When I lived in Europe, I had a German phone number but was frequently living/working in other countries.
