Did you expect any other viewpoint from Prussian memoir writers?
The territory taken in the Rhineland and Saxony was not previously Prussian, or was it?
The Rhineland had been French for twenty years when Prussia was ‘awarded’ it at the Congress of Vienna (where the allied powers gathered to divide up the loot from Napoleon’s empire). The Saxon king was imprisoned by the allies and about forty percent of his country, territory and population as well as army, was taken by Prussia. And Prussia was attempting to take the entire country, just as she had attempted to during Frederick the Great’s time, and by bullying Saxony into joining her in 1806 against France.
Prussia desired to be the leading power in Germany and vied with Austria for that position. Unfortunately for Europe and many others, Prussia did become the leading power in Europe and united Germany under her hegemony in 1871.
As I have already stated, the ‘war of liberation’ was nothing more than a grab for as much German territory as possible, as was made quite clear by subsequent events.
As for Prussia having a ‘major load’ of the wars against Napoleon, the British, Austrians, and Russians had all fought against Napoleon longer and if it wasn’t for British subsidies, the Prussians (along with the Austrians and Russians) could not have kept the field in 1813-1814.