You are doing well. Gear the Phoenix upto all G8 Ezra can go upto G10 if you want. Get Palpatine and Thrawn when you can. Beating thrawn will need some good mods but doable. And keep farming the Empire. Add this guy: Stormtrooper. Make an Empire squad for R2. I used Tarkin, TFP, Vader, RG, Stormtrooper for 7* R2. The good about this team is that 3 of them are pilots of important ships in fleet arena. So I farmed those pilots to G9, Tarkin to G10. The rest two tanks at G8. Plus If you have Palpatine, you will do it much easier but I still recommend farming the five members I told. 3 of them are pilots anyway, and the two tanks are quite useful in TB anyway. Now you have Thrawn and even R2.
At this point you could change your arena from Phoenix to Thrawn lead Empire team. Consisting of Thrawn, Palpatine, TFP, Vader, Stormtrooper or RG. This team is very viable because they get 20% turnmeter whenever they resist or take a debuff from the enemy. So this team is strong against most, if not all, teams that rely on debuffs. This team doesn't need crazy mods compared to others because the leader ability builds up speed by itself.
Then work on other CLS journey characters: StHan, Leia, Farmboy Luke, Old Ben
When you get your CLS, change your arena team from empire to CLS,R2, Han Solo, GK, Thrawn team. You should join an HAAT guild ASAP if you aren't in one yet.
Then you will have to work on Resistance and FO.
First work on Resistance so that you start to farm speed mods. Then farm FO for BB8.
FOST will be a long farm so you should start farming him from right now.
Or if BB8 is likely to come soon, farm FO first, then Resistance. Depends on event schedules. BB8 is needed for Jedi Rey, along with the two veteran smugglers, Finn, and Rey scavenger.
Then you can change to Jedi Rey lead, BB8, R2, OldBen,GK team.
For fleet arena, use Tarkin fleet. along with vader, boba(Or fives), fotp, tfp, Biggs for front lineup for reinforcements: Maul and plus random 2(2 U wing, Wedge, Ghost, Phantom, JC, Ahsoka, Clone Sarg, Sun Fac, Geo soldier...).
Then after you get thrawn, start farming Home One, Ghost, Phantom, and other 3 Rebel ships. There are 6 noncapital rebel ships now so you can skip one Rebel ship and I recommend to skip Bistan, since it's relatively a long farm.
Once you get Chimaera, Start using him in arena right away if your thrawn is over G11, and Chimaera ultimate annihilate ability maxed out.