AS an employee, your 401k contributions can only be done during the actual tax year involved on your W-2....you can't make a contribution to that year after 31 Dec.
There is a "chance" you could make a deductible contribution to an IRA for 2022 (ASAP), but the ability to do so would depend on whether box 13 (Retirement Plan) is checked, or not, on your W-2.....and if checked, yoru income level may restrict how much you could contribute, and still have it be able to be used as a deductible contribution.
See the information at: Retirement Topics - IRA Contribution Limits | Internal Revenue Service (irs.gov)
IF you do make an IRA contribution....remember to let the IRA administrator know it is a 2022 contribution.....and know that it is just an income deduction......not a credit. So that a $1000 contribution would only reduce your taxes by ~ your marginal % tax rate.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
