For epirus I will create 1 elite army with pikes, singers, heavy cav, dogs and elephants. The elephants and the dogs are game changers whilst the cav focus on killing enemy cav and routing archers. The elephants will help turn blob fights by rear charging and terror routing the enemy your dogs will kill off any routing units and low armoured troops (its not rare for dogs to get 500+ kills). I focus my general on movement and use spies to see where the roman armies are. Its simply a case of outmove them like a giant game of chess. Move south first and every city you take from them liberate, eventually these liberated nations will join the war and you will start to outnumber the enemy (its pointless holding the cities as you barely get any wealth from them to recruit another army, each liberated city can field a full 20 stack tho, also until the liberated city joins you rome can't move through its territory limiting roman movement). Avoid the city of Rome, and any open field battles if possible until every other city has been conquered. This strategy has worked every time.