I don't mind Y on a daytime TATL. But overnight, J is much preferred.

One option (I know it's not DL) is rather than hub through ATL, go thru JFK and take the AM flight to LHR, daytime flight. If you don't want to pay for J/F, the daytime Y is not as taxing as the redeye. Going to CDG, it's a bit awkward as you'd need to overnight in NY on the way out and at LHR when you arrive so it comes with some overhead.

Personally, if it's redeye, we go J over and Y back. If we can do the daytime flight, I'll do either, depends on the relative costs.