Good question... I think they're pretty different in taste and how they're made (which is why they taste so different)

Miso and "dwen jang" taste very different because miso is usually mixed with soybean and rice, whereas dwen jang is all soybean. They are also aged differently. Miso is packed into more air tight container, whereas dwen jang is shaped into a block, hung outside to air dry.

The block to hang up outside for air drying is called 메주 (meju) which is form before made into 된장 (dwenjang). There is more process involved to make it into dwenjang. Actually from that meju we make daenjang and soy sauce.

I've really come to appreciate daenjang more than Japanese miso over time. It has funkier, earthier but arguably less refined taste than Japanese miso.