Well, im at like 230 BC and just cracked my first million as the Romani. I conquered Italia and Sicily, and ceasefired both the gauls, disbanded my army
and spent two decades building roads, markets, ports, public health stuff, mines in Southern Italy etc. I now have 4 full stacks (2 on Greece, 1 retraining, and 1 heading north into Provence. Training another 2 at the moment.
You get too a stage, where its almost exponential money growth, no matter what, i just keep making money, especially since capturing Pella (Maks had top tier mine there). Im on Hard map difficulty too, so its not that bad.