No in my opinion it is simply AI Cheating ...
have the same problem, even I have better Tech, better troops, better moal, better troop consistance (2xCav, 4xinf and 2xArt) ... and better foritifications.
It doesn't matter if I attack Ottomans, Bavaria or anything else ... I am loosing always more ... their problem is that I always have more money and so I could buy mercenaries over and over ...
THE ONLY THING THEY HAVE BETTER "SEEMS" to be the GENERALS, as I only have one star Generals as I am loosing always more troops EVEN I ALWAYS win the war. (As I said I have more money, as I own all North America gold provinces and Atecs, Mayas (whole middle America)
I even have choosen the military traits for my country (+50% and I am up at the land tech, most 3-5 in front of my oponent)
It could be two reasons AI cheating or GENERALS ... will see when I could buy that War Academies and recruit high star generals, what will happen.
Bye the way even that PC only attacks my 3star Fort with 1000 infantry he always is faster to conquer it, than I with my full Army (2xcav, 4xinf AND 2xART) ... I am sure he is cheating, even I am winning against him.
SO I THINK THE PROBLEM IS THE GENERAL and if it is that case, it is stupid. As I said I will try to get also (even didn't know if the PC has high star Generals) high star generals and see the difference.
At the moment it feels like AI cheating, even it couldn't win a war with that tactics.