Neither is true. The DPRK isn't trying to pursue a war against its enemies in a military sense. They're trying to extort money from the world community as a price for peace.

North Korea has limited directional options if they want a realistic missle test.

Having one overfly Japan may just be the least politically bad option they have.

Other paths would be toward China, Russia, Taiwan, Phillipines, etc.

Oh, well, yeah, I mean the US still isn't quite collateral though...

huh... I am feeling uninformed. Could you enlighten me why this is the case?