I agree very strongly with you. The FBI doesn't want to seem incapable of solving this (especially considering how many tools they have at their disposal), and

I agree very strongly with you. The FBI doesn't want to seem incapable of solving this (especially considering how many tools they have at their disposal), and if the DPRK did do it, they would have been much more loud about it and likely less sophisticated. The only possibility that I see of DPRK involvement is that they initiated the hacking through the third party and that third party did a way better job than they expected.