Putin started this war and he obviously knew thsy a by-product would be the u.s. draining itself (of weapons and money) propping up Ukraine. I think Putin is taking a long view. Attrition. The Russians know it well. It can apply to western resources and Ukranian lives.
NATO crossed the red-line they had been warned about for decades only after they had built and equipped an army in the Ukraine of 600,000 soldiers.
While at first Putin was trying for a ‘fight until the Ukraine negotiates’ strategy, it didn’t work. When he realized NATO will grind down to the last Ukrainian or NATO soldier fighting in the Ukraine, Russia switched to a war of attrition. Russia is losing soldiers but is confident the Ukraine will ‘run out’ of the resources to fight first. And so the deaths continue.