@xnervwang , I understand your questions but do not understand the situation fully:
(a) I am assuming here that you are US person ( citizen / GreenCard / Resident for tax purposes ) --- when did you arrive here, with what visa and are you still and Alien ( Green Card or Visa) ?
( b) that you have a main residence in the USA ( Rental or own)
(c) you house in China is a second residence and that this was bought before arriving in the USA
(d) this property in China is personal property and is not income property ( yes ? )
(e) you took out a mortgage on the property in 2018 for US$ XXXX ( converted from RMB to US$ at average / actual exchange rate )
1. Thus the remaining mortgage principle should be actual balance converted to US$ using Dec. 2021 exchange rate ( RMB to US$) or the annual average published by the US treasury/IRS not that of 2018
2. even though you are telling the software that you do not have a 1098, just say "yes" to satisfy the software -- it should not be asking that question but "yes" is valid since you are working with the equivalent to 1098 --a bank / lender statement.
Please can you clarify the situation more ( answer my questions above and also why you are having to amend your 2021 return in addition to how are you using the property ? I know in many countries, you take a mortgage and pay while the construction is going one and do not have possession or beneficial possession till after the whole mortgage is paid-off or replaced by a different mortgage ( like the construction mortgage replaced by a regular mortgage in the US ).
pk
