You better double check your bank statements and check your IRS account (both accounts if married) to see what they sent you. The 3rd Stimulus started coming out in March 2021.
https://www.irs.gov/payments/your-online-account
Did you get letter 6475 from the IRS saying they sent you 2,100? They sent a letter for half to each spouse. The IRS records show they sent you the full 4,200. So you each got a letter for 2,100.
That happens a lot. People only enter the amount they got from only 1 letter and miss the other half. And when they check their bank account they find the full amount.
