Ok I found out the problem. I am using simplepbr which comes with its own shaders, which are overridden with render.setShaderAuto(). To enable simplepbr shaders, I need to do so during my init call of simplepbr with simplepbr.init(enable_shadows=True), and avoid setShaderAuto() altogether.
I found this out from this useful thread: Best practice for lighting in a cave or dark house? - #6 by rdb
One important note is that point lights do not cast shadows if spotlights or directional lights are in the scene, so I’ll be changing my point lights to spotlights I guess. Pinging you @Moguri to see if there is any progress on that front.