I know this taxpayer and I think it would not be intentional. I think he just didn't understand. 

I am wondering if I need to amend 2021 and 2022 and report the 1099's that have those dates or just report all on the 2023 return since the money was not actually received by the taxpayer until March of 2023.

It seems like the IRS would have issued him letters indicating he didn't report that interest in 2021 or 2022 since they have been pretty active in checking 1099's.

Arnold