Unless the US is going to try and overthrow the government of NK entirely, there’s no point in making Kim feel less safe. The whole reason they have nukes is because they have absolutely no other options to protect themselves from being destroyed by their better armed and equipped neighbors. They can’t win economically or with conventional military strength. Their two options are:

Diplomacy
Nuclear deterrent

The US has made clear that we’re not interested in diplomacy, so the only thing they can do is build nukes.