Sorry if my Answer is not going to satisfy you fully since im not an Academic historian but someone who did his share in reading and hanging around at University but since this is thomething that catched my Interest as a Native some time ago and no-one else seam to be interested i would start up with the Conclusion i came to find Satisfying:
'Mostly overexegerated and the Turnpoint of an over biased Discussion.'

There is not much to Say about it in the Early time since there was only one relevant Battle won in-betwean the 30years War, in which Prussia and Brandenburg as the second-bigest-protestant-power in the HRE managed to keep more or less 10% of its former Population...not much of a power so, and FredericII.

Yes its true, the Iron Loading-stick for the Muskets of the Fredrirician Army speeded up the Loading-proces compared to a usual wooden one, but firstly this was fastly adapted and secondly the Hohenzollern made a lot of Money by exporting Weapons to whocareswhom, so this would not be a military Secret or an really exploitable advantage if you don't have an Army that is trained for decades without ever facing an Enemy, as Frederic, thanks to his Father the Soldier King who builded this Army, had.(->having a war-advantage because of not fighting any)

Both put together gives you an Significant advantage in Firefrequenzy

but

the Second Tech-boost where the Grenadiers (also fairly common to that Timeperiod) which he used in higher Percentages compared to his Opponents. Since there real Power is in the closer-combat damage the main-tactic for them would be Frederics famous "Advance,advance,advance"...which is practically not fitting with exploiting the faster reload-rate.

There was, in his early time, an Disadvantage in Volonteer-Cavalery troops which where needed to attack your enemies suply-lines (and of cause defend your own). In the end he mostly won his Wars on the green Table, by making a Separatepeace with Austria while his Allies France and the HRE-Emperor(a Bavarian) where still trying to take Bohemia and Slovakia from the Habsburg-Archdutches, or simply because England defeated France in the Seven-Years-War somewhere at the other side of the World.

Don't get me Wrong If they would not have impressed there Enemies they would not have survived this.

But the only thing threatening the Russian suplylines, when they pulled out of Berlin instead of giving Prussia the final blow, where the Austrian troops in Poland. (Austria and Russia had their own Game of Rivalry an comradeship in pushing their borders side-by side into the Otoman territory.) The "Miracle of House Hohenzollern" is in fact not how he made an small Country having an big Army and how this would not only fight one World-Super-Power but three, by defeating their huge Armys... ....because he didn't, but; "what where the Russians really up to?"

Out of this a Legend was born

and out of this Legend a Debate if giving away your society into the Hands of the Military(which in fact was never done by him or his Father or any other Predecessor ) is good or evil by overdoing the Glory or the filth of it.

The Two other significant occasion where Prussia had really something going on at the Battlefield (beside of being in a Coalition of half the World against France) where in Fact carefuly chooses Moments where they could exploit e Technological advantage they had for that Moment to force a decision:

The Bismark-War against Austria which was won by the Needle-rifle

The Bismarck-War against France which was won by Krupp-Canons

In Both Occasions it was thru Political plotting that an Over-self-confident Enemy was tricked into "Jumping into the Knife" And of cause an functioning Army which was able to use the Momentum was necessary.

But the Overwhelming Military Force of Prussia is pure Mythologie one they themselves, and their political Oponents,exploited bravely.

Sorry for my horrible English