You cannot CCU to a phoenix or any other hill limited ships (890, pioneer, Idris, javelins, kraken, etc.)
IIRC, Back when the Connie was split into 4, you had a choice of what to get, but tht required you to have the Connie back near the original kickstarter.
The most reliable way to get one is to buy a pack that includes one, like the RSI complete pack, or one of the St. Patrick’s day packages if you are okay with the emerald.