You write: "Cheap" here means the advantages of scale; the more you produce, the lower the costs.-I mean, if North Korea suddenly one day launches an An-26/32 at Panghyon, I'm happy for them... but surely someone else is funding them to do this.
There is no way North Korea could finance such a program on its own, mainly because of the "economical" problem I mentioned above. "Economical" here means the benefits of scale; the more you make/produce, the lower the cost. If North Korea paid for everything itself, they would have to take a huge loss, or they would have to buy the plane at a very high price to break even. Someone will have to shoulder that huge cost.
I think the main issue for the DPRK is to have the ability to modernize their military and the country and, due to very heavy sanctions and embargoes, they have to do almost everything they need at home.
So our way of thinking about "cheap" is not possible for the DPRK.
If the DPRK used our vision of "cheap" as a basis for making weapons systems, they would probably still only use T-55/T-59 tanks and Scud missiles.
Therefore, effectively excluded from the possibility of buying what they need abroad, North Korea has decided on the autarchic way to achieve the goal in any case, to do so it has had to invest in creating a good military industry.
Therefore I think it is a big mistake to write that it is anti "Economic" if only a few units are made, because in any case they are useful to gain experience and move on to the next step with the small steps method.
Then friendly countries will always be welcome if they want to lend a hand, in the past agreements with other sanctioned countries have brought benefits for everyone, today the newfound friends could make important steps in the aeronautical sector of the North Korean industry, and if hypothetically a civil / military transport aircraft is considered important for the needs of the country, they will certainly not start to do the math if it is "economically" convenient to do it even if it is a matter of a few dozen units.
As if to say, if nothing changes in the international arena (UN Sanctions), better a few than nothing.