Actually, the IRS can take as long as they want. In the past, 21 days has been a goal, but not a guaranty.
The IRS is seriously backlogged this year, due to all the new tax laws and extra stimulus filings, as well as a few million unprocessed 2019 returns left over from the COVID shutdown. Lots of folks are still waiting, so please continue to be patient. Also see:
The IRS is under serious stress — what does that mean for your refund? (msn.com)
What led to IRS backlog: ‘Thin workforce,’ new pandemic relief programs | Federal News Network
