This is very simply about three things, logistics, relevant troops and economy
Logistics- Germany would take much longer to conquer
Engineering would be essential to make the wars much shorter, as infantry units move double as fast on roads, something which is badly needed in a prolonged war. With Guilds and Banking, with the intent of building banking and groceries - this seems and feels more like a peace economy. Maybe we should just stop at Berlin right now, until we catch our breath.
Relevant troops, we need to fill up with lost catapults and lost assaulters, as well as we need new garrison longbowmen to be built. Now, we are not needing knights from Guilds at this point, we are far stronger than the opposition in all respects.
Economy- The more units we build, the more we would have needed Vassalage. We now have bureaucracy, which is a fine peacetime civic. With the technology research preferences, the intended builds and our economic goals and the intended Civic Change, I think we can run a low key pillaging war for a while. The problem of keeping the Romans alive was the risk for a two front war, which we got by attacking friendly Germany. Now we the Romans are ready for a War of Vengeance.
This is why I am gearing Formation promotion units and mounted units to Rome, and Schock and Cover infantry units towards Germany, as Germany got no horses, but more longbowmen and spears ( very few elephants), where Rome have chariots, legionnaires and so on.
For this I have three scenarios:
1. Armed Vigilance, we make peace with Germany, and keep our troops ready in the narrow Cumae-Berlin-Munich axis ready to make a good defensive war till we can make a counterattack on Germany and/or Rome.
This would be the case if we are to rebuild the economy right now.
2. Adjust the German East West border farther North, by taking Cologne, Essen and Frankfurt. This would require us to build more units missing to take these three cities,
3. Full German annihilation would require us to research Engineering before Banking, since we would need to replace non-cavalry via road from cities like NOTA and Riversight, a very long stretch to Hamburg and other far northern cities. Engineering makes wonders for roads.
I would like to see the people to seek to unify policy goals more holistically, not putting together a birthday party wishlist. If we want to reach internal goals like those presented on gold and beacons, let us reach those without jeopardizing these with war efforts. War costs money. And if you want full scale war, give me vassalage, and we will see many and promoted units being built. I can fight all war scenarios, but please give me the right tools to do the job.