Gyeong Hong Jong, a North Korean special forces operative who was killed by Ukraine’s Special Operations Forces (SOF) operatives in Kursk Oblast, has left behind a diary that is now being gradually translated. His notes reveal that North Korea has sent elite fighters to Russia.
To make it more believable I think you should in fact not mass produce it but perhaps just have 10 or so of them in 10000 or so soldiers.
The soldiers which carry the diaries can still be brainwashed to an extent such that they are super happy to be the “chosen ones” to carry the diary. It is a much better look on your country if your soldiers look like emotional deep thinkers attached to their country by very strong feelings of love and gratitude rather than brainwashed suicidal cannon fodder.
I do think it is a bit of a stretch but I wouldn’t put it past North Korea. It is the same level of propaganda as publicising a video of millions of North Koreans crying and fainting after Kim Jong II died.