The answer depends on the end date of the plan year. For example, if the plan uses a fiscal year that ends on January 31 and in January 2022 the employer contributed a matching contribution for elective deferrals that you made from income earned between February 2021 and January 2022, the matching contribution was made for the plan year that ends in 2022 and makes you an active participant for 2022. However, if the plan instead uses a calendar year, the matching contribution would be one made for the plan year ending in 2021 and makes you an active participant for 2021.
So to determine whether or not this matching contribution makes you covered for 2022, you need to ask the employer what the end date is for the plan's year. Hopefully it uses a calendar year and, if so, you'll be able to deduct a traditional IRA contribution. A plan year ending in any month other than December would likely mean that you are covered for 2022.
