Massively increase counter-espionage budgets, to shadow NK agents outside of the country, and counter their malign activity. It may be costly, but the cost of creating a global surveillance state, with AML checks encumbering billions of interactions each day, is bound to be greater. This is just a small fraction of the costs involved:

https://risk.lexisnexis.com/insights-resources/research/2019...

The impact on the developing world is profound:

https://finance.yahoo.com/news/money-reimagined-starve-ugly-...