Squad for a “New” Player (Actually Level 77)

Looking through your roster, you could start working on a phoenix team easily, you have good progress to that. Rex lead is always good and you have 5s, Echo and Clone Sergeant unlocked so that helps If you can get ARC or Cody going you would have a really solid team for a long time. You should have access to all the stores which makes farming most clones easy. You also have a decent start to a rebel team with Ackbar, FBL and Lando. Good thing about phoenix is you get Thrawn and Palp off of it and work towards GMY. Since you have Mace at 7* you'd have a third. I'd pick up Jedi Consular and Ahsoka. Both are easy farms. The only benefit of going after Ima-Gun-Di is his node is the same as the Y-Wing. You have the start of a decent scoundrel's team for some of the events, Lando, Boba, Nute Cad Bane and CW Chewy. I'd finish off Boba, Cad Bane, and Dengar. Zam's not bad either but if you're in for the long haul and want to eventually get Han's MF, like most people do since A) it's iconic and dear to everyone and B) it's an awesome ship to have, you'll want IG-88 and Bossk with their ships and you'll get Jango out of that too so Zam is not that important. I would keep farming Vader, Tarkin and TFP. Them along with Thrawn and Palp will get you R2. If you unlock Palp and thrawn, you can make a decent team with a Palp lead, Vader (especially with the rework), Maul, Darth Sidious and Thrawn.

You have options. The main thing is to come up with a plan, either on your own, or follow one of the guides online and stick to it and learn from your mistakes.