@adkbox below is the official IRS policy; however, I do agree that other than the fact they are so woefully backlogged, it should not take this long to resolve.
Have you reviewed your transcript to see if there is any indication they have it tagged for unemploiyment review? otherwise, I'd go against their advice and call them. it has been 18 months already.
Status of Unemployment Compensation Exclusion Corrections: The IRS continues to review tax year 2020 returns and process corrections for taxpayers who paid taxes on unemployment compensation, to exclude the compensation from income if eligible. To date, the IRS has issued over 11.9 million refunds totaling $14.6 billion. Some taxpayers will receive refunds, while others will have the overpayment applied to taxes due or other debts. The IRS will mail a letter to affected taxpayers to inform them of the corrections, generally within 30 days from when the corrections were completed. See the 2020 Unemployment Compensation Exclusion FAQs for more information, including details on whether filing an amended return is needed.
https://www.irs.gov/individuals/get-transcript
