I agree with nearly all of what you write. One important point that you don't mention is the political "win" for Moscow through this action by Ukraine.

Ukraine is no longer just defending Ukraine, they are attacking. It is no small point and similar to the loss of the moral high ground for Israel by invading and holding foreign territory.

I certainly understand the sentiment, and maybe the risk is worth the reward, but the moral high ground has clearly been ceded (if it wasn't already).