AGI is on line 11 of 2022 Form 1040. The taxable amount of your pension is includible in your AGI and therefore is part of your MAGI. There is no subtraction for a military pension.
See Worksheet 2-1 in IRS Pub 590-A for calculating your MAGI for the purpose of determining eligibility to make a Roth IRA contribution. Nowhere on that worksheet is there any mention of a military pension: https://www.irs.gov/publications/p590a#en_US_2021_publink100025085
