If the Ukrainian conflict settles according to Zelensky's terms, it will send a very dangerous message to other leaders; that they can transform their country to a NATO launching pad, and threaten any sovereign country, without consequences.
The EU stance on Ukraine rewards Western aggression and NATO's expansion. If NATO wins this war and annexes Ukraine, no country in the whole world can feel safe.
The same problem with the same pattern of consequences will appear in Taiwan. The Western alliance arms Taiwan, promises to intervene if China tries to recapture the island, hence it activates the Thucydides trap.