In wages and income, Box 14. Description is E and on my W2 it is described as Military TSP Contribution (Tax Exempt). Which dropdown category would I select?

You should select "Other not classified."  You are correct the code "E" in box 14 is for TSP contributions from tax exempt combat pay which is not included in your W2 box 1.  The box 14 note is for information only. 

[edited 2/14/2023 6:35am PST]

@SteamTrain  @merght 

@DMarkM1 

Did some major reporting change happen this year?

DFAS should know what they are doing, but I thought Non-Roth TSP contributions would be in box 12 with a code D.