I don’t understand the background, what is it what I see?
Back to your question, one thing is that most likely you have loads of bounces, 128 maybe? Try it with 6
It looks like a very diffuse HDRI to me with not that much contrast. Maybe look for a more an HDRI with a bit more contrast.
- Place some objects that cast shadows on the house, like trees.
- Try other textures. The texture of the roof, doesn’t match qua contrast with the texture of the wood.
- Some sharp edges reveal that the geometry is to perfect. Do something with it, like add details, or add some randomness, etc.
And what do you mean with soft: lack of contrast, or that the HDRI is in lower resolution than the scene (hdri looks blurry, and gives gives a kind of DOF effect making the house look more like a toy?)
Cartoony? I think those are the shard edges I mentioned earlier.