KYIV, Ukraine—Ukrainians greeted 2023 with drinks, air raids and a firm belief that their country will fully reverse the Russian invasion that marked the past year with disruption and death.

Their optimism for the new year comes with around 20% of the country still in Russian hands; military and civilians still dying in the thousands; and the economy suffering lasting damage from a war that few Western experts see ending soon, or outside a negotiating table.