415 limit failure across 2 plans

Sponsor has a 401k and an ESOP; two separate plans with two separate third party recordkeepers.  Compliance for the 401k reported ADP test fail.  Corrective distributions were calculated and returned prior to March 15th 2021.  Compliance for the ESOP reported 415 limit fail that involved 1) limiting ESOP allocation to certain participants due to maximum annual contribution in the ESOP, and 2) additional excess contributions to be returned in the 401k, comprised of deferrals and match.  ESOP recordkeeper told sponsor to notify 401k recordkeeper with this information and indicated that the correction deadline is 12/31/2022.  Is this deadline correct for 12/31/2020 plan year end?  Where can I find the guidance that supports this?

https://www.irs.gov/retirement-plans/self-correction-program-scp-faqs

Two-year SCP window. IRS website actually gives an example of 415 failure for 2016 that would eligible for self correction by 2018.