I’m not sure they can sustain it for another four years. The oil price is already below what they need to comfortably fund the war, and some forecasts suggest it could drop to around $45 per barrel. That is far below the level their budget depends on.
So we will see what happens, but I’m skeptical they have the resources to keep this going for that long.
RE: War, Power, and the Hidden Front: Russia’s Internal Struggle