Thanks @DMarkM1. Really helpful information and sorry for an additional question (tax is complicated). Based on the first-year election criteria that you shared, both my wife and I are non-residents at the beginning of the year and residents by the end of the year.
In this case, do I fulfill 6013 (h) that says "the individual must be married to a U.S. citizen or resident alien at the end of the tax year for which the election is being made"? If yes, then my wife and I can have a joint statement to be treated as resident for tax purposes for 2021 (after fulfilling SPT in 2022) and file normal 1040 without the restrictions applied to dual-status aliens.
