"Covered by a retirement plan at work" means that employee or employer contributions were made to the plan for the year for which you are making the IRA contribution.  Simply having an existing retirement account or plan at a former employer would not make you covered by a retirement plan at work.

Of course you must have compensation, generally from an employer from which you received compensation in 2020 or net profit from self-employment to be able to contribute to an IRA at all.