First off, you might want to consider pushing your Phoenix to gear 9 before you sideline them. You definitely can get a 7* Thrawn and Palpatine with them at gear 8, but it will be very challenging (Thrawn especially) and require some prayers to RNGesus, hallowed be thy algorithm. At the very least I'd get Hera, Chopper and Ezra to 9 to save yourself some headaches.
The common wisdom after Phoenix is to work on the requirements for other legendaries and Hero Journeys, which means getting an Empire team for R2, a First Order team for BB8, and the other requirements for Commander Luke and Jedi Training Rey: Farmboy Luke, Princess Leia, Old Ben, Stormtrooper Han, Finn, Scavenger Rey, and Veteran Smuggler Han & Chewie.
You also def want a team of scoundrels for Credit/Droid Heists. Stormtrooper Han and Vet Han/Chewie are all Scoundrels, so they can pull double duty there if needed - and the vets are a pain to farm, so the sooner you get them out of the way, the better. SCOED already listed some other good options a couple posts up.
That's more than enough to keep you busy for a few months, if you want to go hard on legendaries. They are definitely worth it - Commander Luke is a beast on a huge variety of teams, and a Resistance team under JediRey can absolutely crush raids.
Also, if you haven't already, get into a guild that's farming at least Heroic Rancor. OG Han is a monster, and Rancor is kinda dated so even a relatively-low-GP guild shouldn't have too much trouble with it - one guy with a decently geared Commander Luke can solo the whole raid. AAT is nice too, though it's considerably tougher to complete.
Do keep in mind that there are a lot of characters available now as compared to when a lot of the guides were written, so you don't have to 100% follow the popular path to see a payoff. Ships, for instance, give you a whole extra arena and energy type for resource farming, and ship arena is generally much easier to compete in than squad arena. Bounty Hunters have also become a hugely useful faction in terms of the sheer amount of content they unlock.
Ultimately it's a game and the goal is to have fun, though. Sure, Ugnaught isn't very useful, but if you'll enjoy playing with him, go for it. Not everything has to be about min-maxing. Good luck.