@oonske8732 - 80% of the backlog is paper returns.
https://www.irs.gov/newsroom/irs-operations-during-covid-19-mission-critical-functions-continue#collapseCollapsible1639064526818
As of May 27, 2022, we had 10.2 million unprocessed individual returns which include returns received before 2022, and new tax year 2021 returns. Of these, 2 million returns require error correction or other special handling, and 8.2 million are paper returns waiting to be reviewed and processed. This work does not typically require us to correspond with taxpayers but does require special handling by an IRS employee so, in these instances, it is taking the IRS more than 21 days to issue any related refund and in some cases this work could take 90 to 120 days. If a correction is made to any Recovery Rebate Credit, Child Tax Credit, Earned Income Tax Credit or Additional Child Tax Credit claimed on the return, the IRS will send taxpayers an explanation.