i have experience with SLKR, Leia, Rey and JML battles. JML and Leia are hard, high speed and offense on the enemies but doable, 3* mostly. SLKR on the other hand is so unfair. Before they boosted resistance stats in that specific battle(OP states that they have 1000 speed, i would say it is 1200 at least) you could keep Rey perma stunned. Rn you use SLKR stun on ray and before you get chance to swipe with him rey is out of it(stun) and ready to use ult. I stopped even doing it since it is just absurdly unfun. yikes CG, yikes