Candles are weird. If you try to manipulate them inside the editor, it doesn't work very well. As far as I can tell, the reason is that a candle and a lighted candle are two different objects. Comparing them to a brazier, a brazier is the object and it can be lighted or unlighted. So you can build a switch for it that will work. With a candle it doesn't really work like that. I did put it as a report at some point, and they were looking at it.
Lighting in general needs to be looked at in this game. I like to use light and shadow in my designs, and the game as it stands doesn't really allow for that. We need control of brightness, dimness, sharp or diffuse, color, on and off. It would be nice to be able to craft a light switch that would allow you to attach it to a light source. The switch would have the scripting attached to it. I was playing a while back and came across a game built temple or something. As I got to a certain distance, it triggered the braziers to light. We need some way to craft a thing that would provide the scripting.
It's problematic that the light brightness is STILL stacking. By that I mean, one candle or torch, very dim. Two, the brightness of the sun. There is no in between. The last time I played the iron stove was much better, but the kitchen stove, soooooo bright.
One of the other games I play (ARK SE) has a mod that makes all the lights come on as the sun sets, and off again as the sun comes up. This should be an option.