For the current rotation, if you really want to rank up as easy as possible, look for Archivum Sycorax and Hab Dreyko. The two easiest modifiers are Heinous Rituals and Rampaging Enemies. Avoid the combination of Final Toll and Encroaching Garden at all costs, it is 100% a guaranteed loss with randoms. The Hourglass set of maps present some of the lowest success rates.