There is a fundamental disagreement between the US and NK.
NK wants a permanent end to the Korean War, first. That gets the UN out of the NK sanction business.
The US wants a complete and verifiable inventory of all the NK nukes and delivery systems, first.
We are at a stalemate until NK complies.
The US cannot blink, ever, or we go back to the NK wiggle and squirm game that has been going on for 65 years.