Your points are correct, Norbert. And, the splendor of Prussian/German royal lifestyles being referred to as "...nothing in comparison to that of the Russian Empire" is subjectively very debateable.
While many of the Romanov palaces, for example, were more brightly painted on the exterior and had byzantine turets that many feel are exemplory of grandeur, surely the Potsdam palaces, the Stadt Schloss in Berlin, Charlottenburg, etc, are equal or more splendid that those of
Russia. True, the exteriors of most of the German palaces lacked color, but the baroque architecture of most and a the details of the designs make touring the regal haunts of Germany a far more lengthy and intriquing tour than those of Russia, France or England.