Since the war began, a number of supposedly independent ransomware groups have publicly announced their allegiance to the Kremlin and the war effort, and their intention to carry out strikes. So the idea of the January arrests was probably part of a larger pattern of arresting criminals and telling them they get out of jail free if they come work for the state. Whether these particular ones have already been turned into assets useful against Ukraine is not clear. At minimum they’re not working against Putin.

The idea of “ransomware diplomacy” was probably just a side benefit.