You are delusional, the Polish Corridor was given to Poland first of all on ethnic grounds - it had a clear Polish majority over entire history, politically was equally Anti-German, it voted for the Polish Party (Polnische Fraktion, later Polenpartei) in all elections to Reichstag between 1867 and 1912.
The problem is indeed not ethnicity, I agree with you. The problem was that it cut East Prussia off, while giving the Poles no solid access to the sea anyway, for which they needed Danzig. So nothing was really solved: Germany had a problem with its Eastern province of East Prussia, Poland had no port city it wanted, and to take Danzig from Germany was just an injust action.
Therefore the only good solution to this conflict would have been an alliance of Germany and Poland, which would have allowed the Germans free land traffic, and to turn Danzig back to Germany, but give the Poles favourable conditions for using it. At that time, Britain said to Poland that any deal with Germany would have left it to the mercy of Germany - no support afterwards. And that's something the proud Poles could never accept, to be at the full mercy of Germany and cut off from their Western allies. They rather wanted to succeed on the battlefield, to gain even more.
That way no compromise was reached and what came next was the start of World War II with fights in Danzig.
From an ethnic perspective, I agree with you, the Polish corridor was rightly given to Poland. But the problem caused by this, the cutting off of East Prussia, could only be solved peacefully with an alliance - with the consequences mentioned = the English would have given no guarantees. Essentially Poland would have been completely on its own, probably even considered hostile by the English, would have become completely dependent from Germany. Therefore both sides chose confrontation, first diplomatically, then Germany attacked, causing WWII.
It was, generally speaking, a very unpleasant and hard to resolve situation and now we know what came out of it. Nowadays people tend to talk about the "2nd World War" as if it was always a fixed thing. No it wasn't. There were various red lines crossed by different sides at different times, and every transgression caused a new level of escalation.
This is, just like it was in World War I, what makes conflicts which affect various nations, big players and alliances, so difficult and dangerous. It can get out of hand very quickly.
Which is why I always say: Don't make the same mistakes a 2nd time. The only mistake the Western allies made with Germany after World War I, is, that they have waited so long for giving the Germans what they wanted all along. Why needed there to be a Hitler to get it? There were democratically elected Social Democrats, Christian Democrats, Liberals and others around, which just wanted the same and radical elements only profited from the fact that Germans were not getting what was rightfully theirs.
Now some conclude from World War I or II, that you have to be even harsher with a so called aggressor, but there is no proof that this prevents a war, even on the contrary, it causes wars. And it makes, if anything, if assuming an evil dictator, if inventing an evil dictator, the escalation all the easier to justify for himself, for his administration, his people and allies.
If people, like this senior citizen Biden, talk like they do, act like they do, they do nothing to prevent conflict and escalation, but cause it. He did so all along, since the start of his presidency, by doing nothing diplomatically, but only arming up Ukraine and backing up its aggressive claims and policy against Russia.
Poking a strong opponent all the time and saying, "he will beat me, he will beat me, you will see, he is a brutal aggressor..." What is this? A bad joke? Why not stopping poking to begin with? Probably because another big guy in the background says: "You have the right to poke him, he is a bad guy, just poke him. If he gets aggressive, we will help, we want to beat him up anyway and you will come out even stronger than before..."
That's the situation in Ukraine, that's the "American policy" there. They caused the conflict.
If someone wants to de-escalate and prevent war, like the Europeans wanted, start working on a diplomatic compromise with which both sides can live with. That would have been reasonable, but not for the American "regime changers".
Humiliating big powers and nations, for no good reason but hate and arrogance, the greed for even more total power, is no good choice. That's something the USA should have learned from history. Russia was willing to compromise, willing to become a Western ally, but the USA, people like Biden in particular did block them. That was a grave mistake, there was absolutely no justice or reason in what the USA did.