From that link
Prolonging the war as a strategy
According to Medvedev, there is another important reason why the war is continuing: He sees a strategic means in prolonging the war that will help Russia to victory. Medvedev describes Western governments as "decadent" and little interested in distant war events, reports the "Frankfurter Rundschau".
“A distant war will sooner or later become boring, expensive and unimportant [for the Western governments that support Ukraine today], Medvedev writes on his Telegram channel.
Over time, Ukraine will be forgotten by the West. Russia would then have the opportunity to deal the traitor the blow of fate.
But hopefully not before Ukraine is strong and well-equipped enough to recover and maintain it's own territory.