For this, I would assume that there's no choice but to exit the secure area, walk to 2E, and then check in with DL, do exit passport control (good luck!) and then security depending on whether your flight is using K (walk) or L or M (for both you would take the underground little train) and then security on the way upstairs after emerging from the little train. For flights to the USA originating at CDG (as you are since you have separate tickets), even with no checked bags, you seem to go through the same check in and bag drop area before getting to exit passport control.

Two hours is tight for DL TATL flights exCDG.