All biscuits & gravy aren't created equal, so be picky. You want hot and fluffy biscuits with hot and flavorful gravy. Too often the roux isn't cooked well enough and the gravy is pasty, forget it if anything is cold

I can't point you to anyplace that's consistent, unfortunately, and certainly not quick service. Off-site, maybe? Split a side order to see if you like it. Most places probably use a powdered mix.
My favorites are
Sorbet at L'Artisan des Glaces, France pavillon in Epcot
Tuna sandwich at Columbia Harbour House, Liberty Square in Magic Kingdom----lots of good things here.
Citrus swirl at Sunshine Tree Terrace, Adventureland in MK
My kids would recommend
Waffle, nutella, fruit at Sleepy Hollow in Liberty Square in MK
Cinnamon roll at Gaston's, Fantasyland in MK
Sorbet in France

They're looking forward to beignets at Sassagoula Floatworks at Port Orleans French Quarter's food court. I'm skeptical.
Table service
Prosciutto/melon pizza and gelato at Via Napoli, Italy pavilion
Bread service at Sanaa, Kidani----you can get this in Sanaa's lounge to avoid making an ADR. Not on dining plan, though.