its a general ai problem in stellaris, we try to constantly improve the ai but the last pdx changes forced us to scramble some stuff as they reworked alot ai-wise. but be sure we are working on that aswell. i suggest playing on Grand Admiral, maybe without scaling difficulty to get a challenge.

But for the mandalorians and sith: we are observing alot of games and try to tweak both empires to feel more challenging. I suggest setting the crisis strenght a little bit higher as they spawn with more fleets in that case.