I guess the lesson here is don’t attack a trained machine gun group on horseback and without cover.
Sit back, use the rifles the way the Boer War guerilla did: Hide behind cover, shoot one and two at a time, move, shoot again. Use the long range of the rifle...
But that doesn’t match their tribal warfare macho-macho style of counting coup and being a single hero in front of the “braves” - just like in the US western wars.
A lesson the Brits forgot on 1 July 1916.
They didn’t even bring their horses on that date.
Here’s the real lesson: Place your maxims in flanking positions with interlocking fields of fire. That gives you a chance for the full 6000.
A lesson Poland obviously missed when Germany attacked.