instead, we saw Russia use DPRK (North Korean) troops to push back in Kursk.
This move, IMO, is fine given that Ukraine has NATO 'freelancers' and 'volunteers' aka foreign fighters on the frontlines. So same same.
However, given North Korea's moves in the DMZ and other 'exercises' it's pretty clear that these troops are there to get some real combat experience (why?) - you know why.
So it's highly likely you'll see DPRK troops manning arty and other entrenched guns whilst the Russians push back Kursk. Failing or succeeding on this isn't going to stop a nuclear test as a show.
Just trying to "predict" the start is going to be a little tricky, given we're already rolling on.