SIMPLE IRA plans are calendar-year plans even if the company otherwise uses a fiscal year. Your contribution in December 2021 therefore makes you covered for 2021, not for 2022. Your 2022 Form W-2 should have box 13 Retirement plan unmarked if you did not participate at any time in 2022 and the company did not make an optional 2% non-elective contribution for 2022 instead of matching contributions.
Being noncovered for 2022 allows you to deduct a permissible traditional IRA contribution without regard to your MAGI.
