Your comment contains a lot of oversimplifications:

• The options are not limited to "fight in Ukraine" or "fight elsewhere later." A spectrum of diplomatic, economic, and limited military responses exists along a continuum.
• As currently constituted, European militaries lack sufficient capacity to "fight Russia in Ukraine" in any direct sense without American participation, making the proposed choice somewhat theoretical.
• The statement fails to account for Russian nuclear threats that have successfully constrained Western military responses throughout the conflict. This factor would remain regardless of where confrontation with Russia occurs.

Many experts call for the pursuit of diplomatic pathways out of the stalemate to avoid a protracted war and further escalation. The Carnegie Endowment for International Peace has published numerous analytical pieces (e.g., by analyst Eugene Rumer) emphasizing that without realistic diplomatic negotiations about Europe's future security architecture, the conflict risks turning into a frozen, yet smoldering phase for years to come.

https://www.cfr.org/article/neutrality-alternative-ukraines-membership-nato

An alternative scenario is a strategy that involves not "fighting the Russians in Ukraine" but maximally strengthening Europe's own defensiveness and supporting Ukraine to strengthen its position in potential negotiations. Dr Barbara Kunz and Dan Smith from the Stockholm International Peace Research Institute (SIPRI), have noted that the EU and NATO's long-term strategy should focus on scaling up their own defense production and capabilities, not just on supplying arms to Ukraine.

However, instead of focusing on the dynamics outlined above, today’s wider European security debate is very much about Russia’s alleged true essence as an imperial or colonial power. There is no doubt that Russia’s actions, which include invading a sovereign country, and its regime’s rhetoric are deeply worrying and unacceptable. But solely focusing on Russian identity for explanations overlooks the dynamic nature of international relations. Russia’s perceptions of the West and its actions are rarely discussed. Nor is how the West’s actions affect strategic stability. While Russia’s intentions are clearly a crucial factor for European security, debating Russia’s nature tends to be highly speculative.

https://www.sipri.org/commentary/essay/2024/nato-new-need-some-old-ideas