Hey! Glad to hear you dig that idea!
Oof, this is a bit of a tough one. The project came about from not having enough Southeast Asian fantasy media, but there are a few that I really liked and inspired me for this project.
Nang Nak (1999) really shows the mood of the jungle, of living beside the river and how dark it can get. Also how spirits can be just so adjacent in SEA.
Wiro Sableng captures quite a bit of the fun and campiness that I sometimes step into, the wuxia-ness of it also feels similar to what I imagine for Kala Mandala.
Both films are easy to find, youtube and dailymotion.
I (and at least another Malaysian friend) also think Studio Ghibli's Spirited Away is relatively SEA coded.
Hope that helps a little!