[RetroTechie]

Ukraine doesn't need to win this war. It 'only' needs to ensure that Russia holding internationally recognised Ukraine territory, continues to cause a steady supply of dead Russians. Like Afghan fighters continued to inflict losses on Russian troops in their country.

Occupying territory only counts as a win (for Russia) if there isn't an ongoing cost in dead soldiers attached.

Do that long enough, and Russians (public & industrial / economic / political elite) will get fed up enough that "remove mr. Putin from power" will be the obvious fix. And when that occurs, anything may happen. Including Russia withdrawing from occupied territory.