This thesis, referring to an article in The Washington Post, is spread by pro-Russian Telegram channels and media. In fact, it is manipulation. On June 17, The Washington Post published an article titled "With limited options in Ukraine, the US and allies are preparing for a protracted war." The authors of the article wrote that "the US and its allies are preparing for a long war in Ukraine, although the Biden Administration is trying to prevent Putin from winning by sending military aid to Ukraine while trying to reduce the impact of this war on world hunger and the global economy." . Therefore, in terms of "preparation for a long-term conflict," according to the context of the article, it is more about preparing a plan in case of one of the possible variants of the development of events. Furthermore, this is quite logical from the view of responsible state leadership. However, it is the context that Russian propaganda leaves out of the discussion.
The same applies to the "dead-end for Ukraine" issue. The article does include the following sentence: "But analysts say that despite the surge in foreign aid and the strong morale of Ukrainian troops, Kyiv and its supporters can hope for little more than a stalemate with Russia's much larger, better-armed army." And again Russian propaganda took the sentence out of context. In this case, we are talking about the battles in Donbas essentially in "real-time." That is, the assumptions of experts relate to the state of affairs on the part of the front at a certain point in time and do not generalize the opinion about the war as such. Also, the events in Donbas are compared with the Ukrainian army's successes in the Kyiv battle. So, it is generally about certain successful actions of both warring parties.