Sweep reduces drag, effectively reducing frontal area. Asymmetric (single wing) sweep would produce yaw, in that the swept wing will want to lead, as the straight wing wants to trail, no? (Due “differential” drag)
Also, forward sweep is no different than aft sweep, related to drag? What was that German forward swept jet? Also “scissor wing”. (Hansa?)
I am tempted to say also that one wing swept forward, the other back, would fly faster than two straight wings. If both are swept aft or both swept forward, no difference in speed. (With equal sweep) All will fly faster than stock. Think F-14.