OTL Carthage besieged Syracuse in 397-396. They were on the cusp of taking the city. However, disease weakened the Carthaginians to the point where they could not continue. At this point Messina was also under Carthaginian control so effectively the conquest of Sicily would have been complete.
That puts Carthage in direct contact with Magna Grecia across the straits. That little town called Rome is still a minor power.
So, what does this do to long term Carthaginian and the prospects of their current and future rivals and how does this effect things culturally.