Ok ... not sure how you deducted the 2019 expenses on the 2019 return ... that was a mistake if you did.
Since the adoption was not completed in 2020 then you can only use the 2019 expenses on the 2020 return ... there is always a 1 year delay. If the adoption is not completed in 2021 then the 2020 expenses would be deducted on the 2021 return. But if the adoption is final in 2021 then you get to deduct both the 2020 & 2021 expenses on the 2021 return. Read the rules : https://www.irs.gov/taxtopics/tc607
