@Robert Tong ,
So you were a student with F-1 and therefore probably an exempt ( from counting days present ) and therefore as you can see from the above ref'd material you do not need a "sailing permit " and so no 1040-C or 2063. Why do you say you are a Tax Resident filing 1040 in 2021 ? When did you enter this country with F-1 ? Was this is first entry ?
H-1 B is generally an adjustment of status and mostly done while the person is here in the USA or sometimes, have to go out for a few days and re-enter for the change. So why do you have to go away for one year ? Which country are you from ( from your surname I am unable to guess -- beyond my knowledge band )?
pk
