The country is in ruins and most of their fighting age men are dead.
The country is in ruins BECAUSE the russians invaded, and in a country of 44 million people its nonsense to say "most of their fighting men are dead".
The Biden administration is considering a dramatic expansion in the training the US military provides to Ukrainian forces, including instructing as many as 2,500 Ukrainian soldiers a month at a US base in Germany, according to multiple US officials.
https://www.cnn.com/2022/11/30/politics/us-military-expanding-training-ukraine/index.html
The UK is training thousands of Ukrainian soldiers
https://www.politico.eu/article/uk-and-france-at-odds-over-military-training-for-ukrainians/
The Blitz didn’t make the UK surrender and I don’t see why the Russian cruise missile attacks, which are less intense than the Blitz, should make Ukraine surrender. If most of the Ukrainian fighting age men were dead, the frontlines would be collapsing, but that’s not happening.