Unfortunately, if you are "covered" by a workplace plan for even one day, you are considered covered for the entire year. You can always make contributions to an IRA, but you can only deduct them if you are eligible based on your income and filing status as shown on this chart.
https://www.irs.gov/retirement-plans/2023-ira-deduction-limits-effect-of-modified-agi-on-deduction-i...
If the contribution is non-deductible, that is not the end of the world but it does create some paperwork issues. You have three options,
1. Recharacterize the contribution as a contribution to a Roth IRA (if your income allows). The income limits for contributing to a Roth IRA are here. https://www.irs.gov/retirement-plans/amount-of-roth-ira-contributions-that-you-can-make-for-2023
A recharacterization must be done before the filing deadline (April 15, or October 15 if you get an extension.) If you have not filed yet, you can get the extension online now. If you have already filed, you can only recharcterize if you do it before close of business on April 15, and your bank or broker might not be able to do it in time, due to the lateness of the date.
2. Leave the non-deductible contribution in your IRA. Your tax return will have a form 8606 to track the non-deductible contribution. Keep a copy of this form for the rest of your life--you will need it if you ever convert or withdraw your IRA funds, to prove that part of your IRA funds were non-deductible so that portion of the withdrawal won't be taxed in the future.
3. withdraw the contribution that has turned out to be non-deductible. This must also be done by the tax filing deadline. You must also withdraw any gains attributable to the removed contribution, and those gains are taxable on your 2023 return (this year) even though you won't get a 1099-R until next year.
