Can you even file an US tax return if you don't have any presence in the US? How do they even identify you if you don't have US SSN?
"C. Which Form to File: Nonresident aliens who are required to file an income tax return must use Form 1040-NR, U.S. Nonresident Alien Income Tax Return"
https://www.irs.gov/forms-pubs/about-form-1040-nr
NOT YOUR LAWYER. Just providing links to a government website that explains what that government requires of people who earn US income.
Things like "Add lines 25a through 25c". Don't they have computers? Are the forms for Citizens like this too?
https://www.irs.gov/businesses/small-businesses-self-employe...