My Carthage campaign that I’m currently streaming featured Numidia approaching me with an early alliance offer, which I accepted. This allowed me to focus on taking all of Sicily (plus Bruttium, which was needed to support my blockade squadrons). Mauretania opportunistically attacked my Moroccan holdings, and after trouncing my far western army I made the difficult decision to let that area go. I had no objectives there anyways. They conquered all the way up to Tingitania.
All remaining far western defenders focused on defending my two Spanish regions (including my very valuable gold mine), and fortunately for me all the Spanish Celtic nations were busily warring with each other too much to notice me.
Meanwhile my Numidian ally attacked Massasylia, and kept them busy in a see saw war that went on for decades. So that’s another African country I didn’t have to worry about.
After Sicily I was then able to shore up my holdings in and around the Africa province, form a line of coastal regions to Oea, and conquer Sardinia-Corsica. Rome this whole time was unfazed by my presence in Bruttium and focused on a costly war in the Alps (in which their legions were having trouble in).
I was very careful, in Africa, not to overextend and pick up worthless decadent desert regions. This meant fighting defense wars only after I picked up the plum provinces I wanted to develop. This would be a good time to digress on a common comment I’ve seen people make in forum talk: “The constant AI warring force me to take stuff I don’t want! Why can’t I give regions away or let them go free or make them into a loyal lapdog client state etc etc etc ...” And this comment, IMO, is WRONG.
It’s wrong in that the game doesn’t “force” you to do anything. If you are taking regions in a war you'd rather not possess, that’s on you. The game gives you ample resources to fight a static border defense strategy, including multiple fortification options for cities, structures that give free supplies to to your mobile border defense army while on garrison, etc. Rome can even have legions spend money to build forts and limes. And there’s a Hadrians Wall-ish wonder as well. So the tools are present. If you find yourself invading every settled oasis on the map because some tribal horde attacked you, that’s because you lack the willpower to say “no” to an offensive war strategy and the compulsive habit of bloating and blobbing that other games have got you in.
Anyways, digression over and back to my Carthage ... at this point my main goal was to level to a Tier III Merchant Empire, and I found myself stuck at Glorious Republic and 4 tokens. Even with careful defense warfare and a massive commitment of citizenry to Culture, I could not crawl back into the top tier of the CDR. It was then I made the difficult decision to attack my loyal ally, Numidia. They had one of my objectives. Rome had a couple objectives as well, thus it was either them or Rome, so ...
Once I leveled to Young Merchant Empire, my government age plummeted and I was now good to go to build new armies and take on some more regions. I expanded in Spain to form the Baetis province, and had the luxury of a war of revenge against the Mauritanians. I generally took their good regions, then turtled up after that.
Years of mostly defense wars later, Rome finally declared war, on or about turn 100. With Imperial Legions! But fortunately, no navy. And that’s where we are now in the campaign (which continues later today).
The last point I want to make is this: EVERY game is different. We see a bunch of totally different Carthage experiences in this thread. So to say, ‘oh, on turn X you should do this, so on turn Y you’ll be able to do that, because on turn Z so and so will attack you’ is just errant nonsense because each game throws up different curve balls and opportunities at you. I’ve been playing this game since the beta in February, and the replayability of Empires continually astounds me.