A graphic by Chinese artists of North Korea's 841 "Kim Gun Ok" submarine
the author drew the presence of 4 torpedo tubes in the bow, but excluded from the drawing the 2 torpedo tubes in the stern, which were present on the pr.633/Romeo class/Type 033 submarine, since many "authoritative" Osint sources indicate that the North Koreans have recycled at least the entire part from amidships to the stern of one of their submarines of that class, it would be logical to hypothesize that they also kept the 2 TLS at the stern
Or, as another Osint writes (on another forum with the nickname "Rohirrim") who is dedicated to the history of the DPRK navy from its birth to the present day:
<<based on the photographs released during construction, it was thought to be the reconstruction of an old submarine, but in reality a completely different, interesting and unique project appeared.>>
In the DPRK shipyards they built the Type 033 in the past, who knows they may have exploited that knowledge to implement them in the new project and during the construction phase also foresee the elimination of the stern TLS.
The author of the drawing in the box of the first photo, the characteristics of the stern and the overall dimensions make it look more like the Project 629 Golf class than the Romeo class /type-033 both depicted there
I remember that a couple of Pr.629/Golf class, together with 6/8 Pr.641/Foxtrot class (from which the Golfs are derived) were purchased for scrapping by the DPRK at the beginning of the 90s of the last century from the Russian fleet of the Pacific which had abandoned them.
And that this new submarine (841) could have been built taking into account
the knowledge acquired on these pr.629 Golf Class and pr. 641 Foxtrot class, referring to the stern.
Furthermore, Kim Jong Un surprised everyone, and "841" is in fact different from all the hypothetical drawings that hypothesized its configuration published by the various Osint.
So I also think that the North Koreans took advantage of the knowledge acquired from the submarines to which they had access and that they also used some structural elements and equipment already produced for the submarines of previous projects.
Materials, equipment, etc., already made, known for some time and tested in operation, are inserted and adapted into a new project.
This choice certainly accelerated construction, may have reduced some technical risks, and may have reduced construction costs.