I ended up cancelling my last trip's Carnation Cafe breakfast reservation because looking at the new menu and recent reviews, it just doesn't seem to be what it used to be. Which is such a bummer because going there for breakfast was a trip tradition. However, lunch there is still amazing! So maybe try to snag a lunch reservation if you can.
For breakfast, I agree that Ronto Roasters is a delicious quick option. It's usually a short or no line at all, and Galaxy's Edge has plenty of seating in the morning and is super quiet because everyone's rushing to RoR so I don't think Ronto's is most folks priority. My husband loved the breakfast wrap it was one of his favorites the whole trip.
I'm not sure where you're staying, but Mimi's Cafe near HOJO is really good. They have great deals that they send out frequently if you sign up for their email list.