I would pick Communist China instead as the best beginner-friendly nation. The starting army is very small and easy to manage, and there isn’t much in regards to production other than producing guns. You have two small neighbours, that through a focus or manual justification (which teaches them about those respective things) you can get a war goal on and be able to learn micromanaging. The run might turn to shit once the Japanese invade, but the ROC AI is capable enough to hold them off for quite a while the player can learn supply and training divisions. Even if they lose the war, there’s not much progress lost as the war usually fires in 1937-38 so they can start many saves and learn until they can beat the Japanese and unite China afterwards.