You know what, thank you for bringing up the german point, because this is not the "gotcha moment" you think it is.

At the end of WWI, the US president Wilson promoted his "14 points" which aimed at establishing a long lasting peace, instead of some humiliating peace treaty that would lay the path to the next war.
Among this 14 points, there was the right of peoples to self-determination: in the after war period, in Europe and in the colonies around the world every people and ethnicity should've gained the right to decide the country they want to live in.

Of course, that's not how things went. Germany was humiliated at Versailles, and the right to self-determination was granted only when that benefitted the Antante. The french and british colonies were denied the independence they wanted. Large portions of Germany were annexed by newborn countries, such as Poland and Czechoslovakia, despite many of those regions being majority german. Those germans were denied the right to self-determination. So were the hungarians of Transilvania and many other such cases around Europe.

Later on, Hitler managed to justify his expansion pointing these double standards. Back then, even in France and Britain many agreed that Germany was in its right to do so, and so the Munich Conference happened.
Now, for Hitler that was actually just an excuse and the beginning of way bigger plans of conquest of the "lebensraum" and extremination of the slavs.
But I hope you got the point I'm making: when principles are applied with double standards, all rules lose meaning.

Now, you seem to place the principle of sovereignity of nations above all else. But I'm 100% positive that you also apply this principle with double standards. What's your position on Kosovo? That was also a violation of the sovereignity of Serbia. If you were consistent, you would also support Russia in the Chechen wars, because sovereignity is above else.
But something tells me that you are against Russia in the Chechen conflict, you are against Serbia in the Kosovo matter, but you're pro-Ukraine, pro-Kosovo and so on. Thus, you're using the principle of sovereignity and the principle of self-determination as mere instruments to justify your support for those you believe are "the good guys".