Your theory is interesting, but the most popular social network in Russia is Vkontakte, not Telegram. It is indeed controlled by the government and any "illegal" liberal channels are banned on sight.

> If that's true, then there can be only two primary interpretations

There is a third possible explanation:

3. This particular war is full of misinformation and lies from both sides. Telegram can be used as a tool to spread your disinfo, masking it as truth.

I really doubt that russian military uses Telegram to coordinate anything, and if they do - it could be rare cases where soldiers haven't gone through any special training. But I can see how Telegram can be used to share other non-vital data. If it's true, then surely it's not incentive from above, but initiative from below.

You should keep in mind that it's not professional specialists on the battlefield, but mostly people who've been regular citizens just a few years ago.