Soft key is not working...

The Home key was replaced and still doesn't work and built-in soft key doesn't work? Could try backing up all your phones data, then reset the phone. Also, those Cables can be really flimsy, plus im not sure of this one but now a lot of home buttons with touch ID are paired to that phones motherboard, and a new button would have to be reprogrammed. Other than that, You could try putting a different rom or atleast launcher on the phone, a lot of free launcher will offer a way to reprogram main functions with their Icons,docks, and widgets if you're okay with ads they are free too. Also worth considering dead spots on the bottom of the screen.