Yeah that is the problem isn't it. phoenix vs phoenix never ends. we should realize starting with phoenix is not as ideal as we think
Besides, phoenix at higher level win 100% against NS. plague almost never lands due to kanan's unique and phoenix end up with full prot/health left.
That doesn't mean phoenix can easily beat ns. due to low dps it takes a long while, but it just does not lose at least
That said Kanan, Chopper, Zeb must be in your line for maximum health/prot regen.
For 5th Sabine is better. She helps dealing with Acolyte.
For teams without Acolyte, you can use Ezra as well
Or for short term fix in case you don't have sabine, use a good counter to acolyte as 5th instead of ezra.
Baze is great with his aoe dispel, but problem is he does not have enough health gain to shake off the plagues. Lando can be good too, he is very squishy but he has the dps.
IPD, B2 are good too although they are hard to earn