<Snipped quote by Dinh AaronMk>Religion was one sticking point for Frederick William III. So I wanted to cover it. Also long term said attempt had far reaching consequences. It can be reasonably said that in this timeline there will be no Kulturkampf, or if it still happens it'd be quite different. I know quite a few things happen but as a non-German I am not as familiar with this period even after weeks of sporadic research so I left it there. It took me half a hour to confirm that Prussians do believe in God-given right to rule (granted, I wanted to make extra sure for some OCD reason).
Another problem is that between 1809-1825 the details are a fuzzy mess thanks to Nappy destroying Prussia in this timeline and that there aren't enough details in the OP and the Char section to have me know whatever the hell I can even include. A destroyed Prussia is also a gigantic butterfly effect for, surprise, Prussia so I preferred to gloss over the pre-1825 era.
I did include enough implications about social changes to know more about this Prussia. For example it being mainly protestant and liberal-ish leaning gives it less favor by certain German states so Austria has a bit more of a leeway. OTL, the German Empire united by Prussia was almost set in stone after 1815 and Austria was desperately trying to unfuck their very slim chances (and of course failing). This Prussia, ekhm, Prussia-Saxony is weaker than OTL, has a bit more mixed support and didn't exist when OTL the Frankfurt assembly wanted to crown the Prussian king the emperor of Germans.
I do plan to have other sections than just history in the writeup, hopefully it clarifies things further. For example Prussia didn't get all of Rhine-Westphalia. They have a presence there but mostly their pre-war territories. This will also have an impact on Berlin's development and generally the Prussian industrial power. On the other hand they got all of Saxony but then effectively also lost it (it becoming a separate state under the same king). So yeah, an interesting scenario IMO.
Well in so far as apps, the only major thing written thus far was that the British let the Prussians take over Hannover for them in an effort to mostly quit the continent. But some things to consider for Prussia:
The post-Napoleonic era is mostly dominated by the politics and intrigues of Austria's prime-minister Metternich who held particularly conservative and anti-revolutionary views and held in high esteem the period before Napoleon and the Revolution that Europe was in. After the final end of the Napoleonic regime IRL and OTL he would have orchestrated to the best of his abilities a sewing together of Europe of old that abided the line that there were people who deserved to rule, and people who deserved to rule; the French, British, Russians, Prussians, Turks, and Austrians namely as the only acceptable rulers. While he abided by a Edmund Burke style of conservatism he was checked by the Emperor who even more conservative and reactionary than his minister just abided by ruler-ruled and there shouldn't even be any stick for the carrot.
But remember too, Vienna was occupied by Napoleon at least twice, so the Austrians aren't as competitive in the German sphere either. Which leaves up in the air what the status of the Austrian-lead common German tariff zone was and their insistence that newspapers and universities needed to be watched and censored to mitigate liberal politics. Both of which over time faded and dissolved over time because it was outside the limits of Austrian influence.
But at home in Prussia, in-so-far as Prussian internal development goes the liquidation of the Junker class would probably play a great deal of effect in what happens. Historically serfdom was abolished but in practice many of those serfs were kept on as tenant farmers especially after the Napoleonic era. The historical effect being that the Prussian Junkers could keep managing to keep a lot of rural Prussians impoverished as a terminally indebted rentier class and they could keep ruling the countryside; also the entry of schnapps and cheap high-alcohol liquors. OTL the land management of the vast estates of the Junkers was abolished and the properties divided up and auctioned off. The result of which may be many more independent farmers in the countryside, and the aristocracy forced into other professions or having to purchase their way back into their old estates like the returning emigres of France. In so far as this goes for Prussia, the new post-Junker rural small-holder creates a much larger group of people more independent than before in terms of being socially, economically, or politically independent. And in an RP that's supposed to be geared towards eventually mass revolution: there may be the main concern.
EDIT - in general I don't think notions of "X people being Y in nature" is any idea that holds water since this sort of thing comes out of a multitude of more directly felt 'physical' experiences. If I were to guess an innate support of the Prussian monarchy would have once been something laundered down to the people through the landowners, their role in the military, and how Germany's major manufacturing bases - Berlin included - fed and supported that institution. But if the cycle is disrupted then it can be different, especially if the King, being supportive of the old aristocracy, whose now soul bastion is the officer schools and clubs, becomes only a monarchy for them and meanwhile small and medium finance is being built up off of small property holders doing what small property holders do.