As you might now around March 2021, the IRS approved the $10,200 income exclusion for unemployment benefits.
The IRS notice IR-2021-71 mentioned that there is no need to file an amended return and that the IRS will recalculate taxes on unemployment benefits. The IRS expects that the refunds will start in May, 2021 for those that did not include the income exclusion for unemployment benefits as this change in methodology happened in the middle of tax season (March 2021) when some taxpayer had already filed their returns.
The legislation, signed on March 11, allows taxpayers who earned less than $150,000 in modified adjusted gross income to exclude unemployment compensation up to $20,400 if married filing jointly and $10,200 for all other eligible taxpayers. The legislation excludes only 2020 unemployment benefits from taxes.
Link – Exclusion IRS – https://www.irs.gov/forms-pubs/new-exclusion-of-up-to-10200-of-unemployment-compensation