I read an interesting suggestion recently. It may even have been in this forum so, if that's the case, apologies for repeating the point. How about dropping millions of smartphones into their country, and arranging for a satellite or two to provide wireless access - or planes flying overhead? A regular WiFi signal wouldn't be strong enough for area-wide coverage but perhaps we could either broadcast much stronger signals on those frequencies, or modify the phones for different frequencies.
We've been broadcasting into enemy territories on shortwave for decades, as well as flying planes overhead that broadcast radio and TV signals to citizens in those lands. Dropping phones and providing internet access is simply the modern version of those time-honored techniques. The population of the DPRK is ~25 million. 5 million phones @ $200 each = $1B. Then there's the cost of providing the internet signal. Sounds feasible.