My homemade nasi lemak sambal always tak jadi, either too sweet or not lazat. Tips?

The secret is patience and the onions. Real good sambal tumis needs you to caramelise a lot of sliced bawang besar (big onions) low and slow until sweet and jammy, that's where the natural sweetness and that dark glossy look comes from, not from dumping sugar. Steps that fixed mine: (1) Blend dried chillies (soaked) with fresh chillies for colour and kick, plus garlic and shallots. (2) Tumis the blended paste in enough oil on low heat for a long time, like 30-40 minutes, until pecah minyak (the oil separates and floats), this step people rush and that's why sambal pucat and raw tasting. (3) Add tamarind (asam jawa) juice for that tang, a pinch of belacan optional, and only a little gula melaka to balance, not to make it dessert. (4) Add the sliced onions and let them melt in. Salt to taste. Low heat, long time, pecah minyak, that's the whole game. Once you nail pecah minyak your sambal will look kopitiam standard.