You report unemployment income in the year that you receive the payment. It doesn't matter when you applied for it. If you did not receive any payment in 2020, and you did not get a 1099-G for 2020, you do not report anything on your 2020 tax return. The payments that you receive in 2021 will be reported on your 2021 tax return that you file next year.
Note that some states don't mail out Form 1099-G. You have to access it on the state's unemployment web site. You might want to check on the web site to make sure that they did not issue a 1099-G to you for 2020.
Since it is an income tax and you did not receive the income until 2021, it is not included on your 2020 return.
unfortunately, i believe the answers above me are correct. same thing happened to me which screwed me over by around $3,000
Yes. The answers by Champ @rjs and Tax Expert @ColeenD3 are correct @doorz50. Income is reported in the year received, even if was supposed to be paid in the prior year, but delayed.
The IRS has a concept called constructive receipt, meaning income is "constructively received" when an amount is credited to your account or made available to you without restriction.