Let's talk early game and costs - I think this might be helpful in illustrating just how powerful just two of Phoenicia's bonuses are.
One of your first districts should be the Government Plaza, which costs 30p. Right off the bat, you get free trade route slot #1 AND a governor promotion, which could be given straight to Magnus to chop the Ancestral Hall.
Production cost so far = 30p
Trade routes so far = 2
Your next district should be the Cothon, which (since it's a UD) costs 27p. BUT WAIT! Your Government Plaza gives you 50% production towards districts, which translates to a real cost reduction of 33%, or an actual cost of 18p.
Production cost so far = 48p (this combined cost is less than a single standard district, I might add)
At this point you can go in several different directions:
Ancestral Hall (150p) -> extra trade route + its bonuses
Lighthouse (105p) -> extra trade route
Settler (80p, +30p per Settler)
It might be good to get that Settler out ASAP, OR you could chop the Ancestral Hall to get an extra 50% towards Settlers AND extra trade route slot #2. Either way, you'll soon have the Ancestral Hall up and running. Let's go with the Ancestral Hall, since it also gives us another lovely governor promotion for Magnus.
Production cost so far = 198p
Trade routes so far = 3
Most everyone else still only have 1 trade route slot.
Now you can go nuts for Settlers. You could slot the Colonization policy card for an extra +50% production, but you'll only start seeing the benefits from that at Settler #4 or 5. Instead, I'd use that slot for something else.
Here's a chart showing how many turns it will take to build a Settler assuming a production of 10. The effect gets more pronounced the higher your production.
View attachment 516177
Competing civilizations can compete pretty closely until you've gotten your 4th or 5th Settler, but at the opportunity cost of slotting Colonization AND they'll have 2 fewer trade slots in the Ancient Era. You could use your 3 (or 4, if you built the Lighthouse) trade routes to generate gold for you to buy units/buildings/etc while your capital just churns out Settlers, using Magnus to avoid losing population.
Each of those new cities will come with a Builder and will immediately build Cothons/Lighthouses, for additional trade routes.
By the end of the Ancient Era, it's not unreasonable to think you'll literally have 2x the cities and 3-4x the trade routes as your competitors.
Yes, you might have to research some techs that usually you would wait on, but isn't the whole point to tailor your playstyle to your civ's abilities? Besides, the extra science+culture from these cheap early cities means you'll be able to make up the difference later on anyways.
Add in to that the bonuses towards Naval units in conjunction with the Naval production cards, and the Cothon is one of the best, if not the best, UD in the game. Late game coastal cities with a low production of 35 can still churn out Battleships in 5 turns.
View attachment 516178
I haven't even talked about the other aspects of their design. But already, the Phoenicians are expansionist
monsters.