The main outcome of a war is loss of lives and infrastructure. Political changes are minor; maybe they will start teaching the language of the invader in schools as an elective... Maybe restaurants will get new foods added to the menu. Maybe taxes will go up a little... A bit more immigration from that country... Money will go to a different set of politicians.
But if you want a modern proof; look at Iraq and Afghanistan... Under US occupation for many years. They have the same people, same language, same culture, same everything as before... It's like they never lost any battles. Look at Germany after they lost WW2; they still speak German. Their cultural identity is still very strong; maybe it affected their foreign policy a little but apart from that, it's hard to tell.
War is truly useless except for those selling weapons and for a couple of big companies that are trying to acquire some mineral resources or securing some trade routes. There's really no other purpose.
My ancestors are from a country which (during the French revolution) had voluntarily changed 'ownership' from France to Britain and later back to France again. They still speak French. Nothing changed, at all, except for the fact that the elites conveniently avoided the Guillotine... Fast forward 300 years and you can't tell any cultural or economic difference at all from the other neighboring nations which remained under France and had experienced the Guillotine; same GDP numbers, same culture, same everything.
Anglo-Saxons like to make fun of the French for surrendering easily but as a regular citizen, it actually makes logical sense. I think it just shows that the government is better aligned with the interests of the people.
Strategic surrender is smart; if you know ahead of time which force is most powerful and can evaluate it objectively, you can save yourself the trouble of dying and you end up with a better outcome than you would have otherwise. It's risk management.
Of course, the Swiss are even smarter for staying neutral but France is too big to take a neutral stance (and they can actually drive outcomes) so they take one stance and then back-peddle if the tide turns.
And France does something else really smart which is; they embrace internal opposition; so if the tides turn, they allow the opposing elite take control without any fighting and it looks like France was always on the winning side.
Almost nobody recalls this, but during WW2, France was actually on the German side; president Philippe Pétain allowed the Germans in. But then later General De Gaulle pushed back when it looked like there was a good chance to turn the war around. And now everyone thinks France was always part of the allied forces.
French people hacked politics. I think now Americans are now also doing something similar. This is why the country is divided IMO and it's smart. Internal division is the cost of guaranteed victory.
It works so long as the population is politically flexible and only focus on what's important to them. If people don't mind changing religion or language or some laws, then it really doesn't matter who wins the war. If the enemy doesn't have clear objectives for a war, then the loser of the war can still control the outcome.