the only boxes in the 2022 w-2c that should have changed are 3,4,5,6 for which an amended return is not filed.
repayment in 2023 entitles you to a potential tax break in 2023 not 2022
if the repayment in 2023 was more than $3,000 (gross pay) you can take:
1) as a deduction on schedule A line 16 denote as IRC 1341 repayment OR
2) recompute the taxes in the year you received the payment by excluding the payment. the decrease in taxes is taken as a credit on schedule 3 line 13b
you do not amend 2022 for the repayment
if less than $3000 sorry the tax laws do not entitle you to any recovery.
https://www.law.cornell.edu/uscode/text/26/1341
