Do I check the "Worked outside the U.S." box if I'm a DoD Civilian stationed in Germany and paid by the U.S. government.)

[DoninGA]

No, since you are a US government employee you do not check that you worked outside the US.  You will enter your resident state as of 12/31/2023 and when asked if you worked in another state just answer No.  And also indicate you did not make money in any other state.