Your narrative on the Winter War is very flawed. For starters, it was not fought before WWII, but from late November 1939 to mid-March 1940, which puts it between the invasion of Poland and the fall of France. It was a part of the broader joint German-Soviet attack on smaller European democracies in the early part of WWII. The secret protocol to the Molotov-Ribbentrop pact signed in August 1939 between Germany and the USSR that divided Europe left the USSR free hands to invade Finland. Immediately they began pressuring Finland and conducting false-flag operations like the shelling of Mainila to accuse Finland of hostility and demand concessions. When the talks broke down, the Finns woke up on 30 November 1939 to the surprise of Russian bombers dropping their loads on Helsinki. So much about "choice".

Pinning this on "the false assurances of then western powers" is just rubbish (with a very modern smell), nor was there anything comparable to the international coalition currently supporting Ukraine. Finland was very much alone. Even the Swedish state hesitated and lot of support that is counted in statistics as "Swedish" came through volunteers instead.

The war ended not because "they prioritised people and soldiers over territory and their own ego", but because Russians had broken through the main defensive line and the situation had become critical for the Finns and making territorial concessions was considered the less risky option. The Finns were afraid that if the war dragged on, Germany would enter the war in support of the USSR. Germany was about to invade Denmark and Norway (April 1940), after all.

Finland did not believe that territory was unimportant. When the major fighting broke out on the eastern front in 1941, Finland fought three years to regain their lost territory in the Continuation War of 1941-1944, and the USSR ultimately settled for far less than Russia is demanding from Ukraine.

The situation is nothing comparable to Ukraine's present day, because Russia has been stuck for years, the defensive lines hold well and the risk of sudden breakthrough is minimal, while Ukraine is able to deliver increasingly severe and disruptive strikes on the Russian rear. Since the introduction of improved drones in February-March 2026, the balance of power has been visibly tipping in favor of Ukraine, and the FP-7 and FP-9 ballistic missiles that are expected to enter service in the coming months will shift that even more so.

As to neutrality, Finland didn't join NATO because a 80-year-old clock ran out, but because the unprovoked nature of the war against Ukraine and the scale of it proved neutrality as an unviable option. There's simply no hope for any country in Europe to avoid such invasion without betraying their independence and becoming a colony of Russia, nor to stand against such onslaught alone. Even with pooled European resources and additional support from all parts of the world, it's still very difficult, as we can see from the news.

Ukraine pursued the same kind of "sitting on both stools" neutrality and it didn't work out, because that did little to slash Russian ambitions, but left Ukraine without much stronger foreign support in the initial stages of the war.

There's a reason why from the arctic tip of Norway down to the hot deserts of the Middle East, not a single neutral country remains on Russian border anymore. What you are suggesting is exactly the kind of recipe that led to this war: isolate your country from allies and hope Russians don't come to attack you. That is not a responsible statesmanship.