The "331" play does not work that well anymore.

This is a difficult time, as you are trying to slip between two big holiday periods (western and Chinese new years).

You might try calling DL and seeing what they can do with an outbound around Jan 11/12 or such and the return specifically on Feb 2/3/4. On the outboud, that should just be a generally more open date, and the return, these are the only date that work before the KE blackout dates.

dl.com is unfortunately still not your friend here.