I'm not implying it is large, just pointing out the fact that it is much larger than you stated earlier in the thread and includes countries that are not pariahs, in a few cases our 'friends and/or allies'.
Why do I keep harping on it? Details matter. Also, while North Korea's arms trade is small compared to the larger arms sellers they still make an outsized impact by supplying arms to folks who would otherwise not be able to get them, much like Iran supplying arms to the Huthis, Hezbollah and Hamas resulting in them having a global impact on trade, among other things.
Another point, that you can see reported on if you dig deep enough, is that the less 'well defined' arms trade is substantial enough to fuel disruption in less stable regions and enables countries that otherwise would not be able to buy or sell arms to do so. I am not talking about Iran or other 'pariah' countries directly buying or selling arms but trade through third-party countries that includes 'friends and/or allies' of ours, who often knowingly or willfully turn a blind eye due to a variety of factors. Just how do you think the Iranians can still fly their F-4's, F-5's and F-14's? It isn't just their engineering acumen or their more flexible safety standards. For a longtime international pariah like North Korea that area is one that they are certain to be neck deep in.