The Mongols were not cowards I think?
Just finished “Empire of the Summer Moon” which was about the 40 year campaign against the Comanches. As light mounted archers similar to the Mongols, they had 1 glaring weakness... They’d typically refuse combat against a serious mounted opponent aggressively handled and frequently not engage at all. The Mamlukes were heavy cavalry and so I suspect the Mongols had similar problems.