The deadline to obtain a return of this excess contribution was April 15, not the due date of the tax return. The excess will need to be included in income on your 2022 tax return. The excess contribution does not constitute an addition to after-tax basis in your 401(k), so it will be taxed again when distributed as Opus 17 said; that's effectively the only penalty. There isn't much point in obtaining a distribution of the funds now since these funds will be taxed the same whenever these funds are distributed.
