It is collapsing. Some people have interpreted the news as the economy being at the brink of an immediate collapse, but articles I have read have talked consistently of end of 2025/early 2026.
The difference is, in 2022 and 2023 it was assumed that once it becomes clear that the Russia's economy collapsing will be inevitable unless they immediately end the war, they would indeed end it. Now it's clear that they will indeed go to the very end, allowing their economy to collapse and then the war ending as a consequence of that.
So, yes, it was predicted that the economy will collapse by 2026, and the war would end in 2022 or 2023 to avoid that. But, the timetable of the actual collapse has not changed. Or, at least not the timetables I've been seeing.
I have not heard of another batch of NK soldiers after the initial 12000. There are talks about them possibly sending another 12000.
With the Russia losing 1300 soldiers per day as dead and wounded, the NK troops cover 10(+ maybe another 10?) days worth soldiers.
The Russian army is shrinking by about 15 000 soldiers per month. That was canceled out by NK troops for one month once, and possibly another one soon.