AI is very passive.

[Battlus Lostus]

Started playing this mod recently as Wurttemberg on medium/hard. Usually I wait for someone to attack me and then fight back, but nobody attacked me after 50 turns so I started a war by myself with the Catholic league. When I besiege their cities I can just wait 9 or 10 turns and take them without fighting . Only once they broke a siege by attacking my army with a full stack they had nearby. But they never attack my cities or forts even if they are an easy target. An Austrian army appeared out of nowhere with a full stack and besieged one of my forts which only had one militia unit. The next turn they left the siege and disappeared.

[Der Böse Wolf]

Maybe try VH/VH?

[Antiokhos Euergetes]

Maybe try VH/VH?

Did you have a more successful campaign? I found the AI a bit passive too, unless I played as the Dutch in which case the Spanish were hard core. I lost a number of battles against Tercios