That's a very good breakdown (from me who knows nothing). Russia has done poorly but Ukraine's military resistance isn't sustainable, and shyt is about to get a lot worse.
At some point a nonviolent strategy by Ukraine would very likely be a best-case scenario for both the people and the government. Putin is looking hardened and as if he wants to win at all costs. The final results of war would be absolutely catastrophic for the Ukrainian people.
But what if Ukraine, at the point when they still hold the capital and main cities but Russian advance appears inevitable, calls a unilateral ceasefire? Not a surrender. Refuse to hand over the country, refuse to give up the leaders, refuse to supply the Russian soldiers, but don't fire any more shots. Continue filling the airwaves with messages about how horrible the Russians are and what a horrible thing they're doing to the country, and demand sanction continue until Russia leaves. What is Russia going to do, just keep bombing people who aren't even resisting? Are Russian soldiers going to shoot their Ukrainian brothers unarmed? Are they going to break into their homes and steal their food? Sure, the country will be occupied, but right now the #1 thing doing damage to the Russians are the global sanctions. How long will the nation accept a crippled economy AND having to supply a huge occupation with zero benefit for themselves? Ukraine can watch the country whither without having to watch their own infrastructure and lives destroyed.
It would be the most powerful possible image to the planet. Every day that Russia did anything to the defenseless Ukrainians, it would cement global resolve to not let Russia get away with it. Every day it would make Putin look worse in the eyes of his own people.
It's not a strategy without risk and loss - yes, some people will be killed and some shyt will be taken. But far far less than would be lost in war, while also completely controlling the narrative and giving them the absolute best chance to turn the Russian people against their tyrant.