Read the IRS rules and worksheet ... you don't just get 20,400 as a married couple for the exclusion ... it is UP TO 10,200 per person :
Note. If your modified adjusted income (AGI) is less than $150,000, the American Rescue Plan enacted on March 11, 2021, excludes from income up to $10,200 of unemployment compensation paid to you in 2020. For married taxpayers, you and your spouse can each exclude up to $10,200 of unemployment compensation. For example, you file jointly with your spouse and your modified AGI is less than $150,000. You were paid $20,000 of unemployment compensation and your spouse was paid $5,000. Report the $25,000 (the total amount of your unemployment compensation) on line 7 and report $15,200 on line 8 as a negative amount (in parentheses). The $15,200 excluded from income is all of the $5,000 unemployment compensation paid to your spouse, plus $10,200 of the $20,000 paid to you. If your modified AGI is $150,000 or more, you can’t exclude any unemployment compensation. Use the Unemployment Compensation Exclusion Worksheet to figure your modified AGI and the amount to exclude. If you file Form 1040-NR, you can’t exclude any unemployment compensation for your spouse.
https://www.irs.gov/forms-pubs/new-exclusion-of-up-to-10200-of-unemployment-compensation
