International student applying from US high school vs high school in home country

I’m an International student from Europe. Will my chances to get in top US university will be bigger if I’ll graduate from US high school with not very good gpa VS if I’ll apply to the top US university from my home country but with better GPA.
Let’s say everything else (SAT, activies and etc.) are the same.

Impossible to say since each school will have its own policies, and since the competition – both domestic and international – may differ year to year.

Why would not get a good GPA from a US high school?

And what’s your financial situation like? If you have the money ($70,000+ per year) there are many very good universities that will accept you even with less-than-perfect grades – and that’s true whether you apply as an international student, or domestic.