Pepper is one of the most finicky cats I have ever seen, not in a bad way though. She refuses to eat anything that resembles human food, the problem is that this includes canned or soft cat food.
Anyone with a lot of experience with cats and dogs will tell you that dry food is not enough, no matter how healthy it is, because it can give them constipation if they don't drink a lot of water as well.
Another benefit of soft food is the enzyme content. Animals need exposure to certain enzymes, bacteria, and chemicals that don't survive the drying process. These ingredients are preserved in canned foods.
The enzymes and bacteria will help the animal digest food more efficiently, thus allowing their bodies to absorb the important nutrients easier. So it is important to get get cats and dogs to eat some raw foods, canned or other soft foods will suffice. If they refuse to eat it, you have to explore a bunch of flavors and textures.
Pepper likes gravy, she likes the soft and canned food gravies so much she'll eat some of it to get the flavor. So I am buying those foods with gravy and "soft centers" and giving her three choices at a time.
One choice is the heavier healthy dry foods, she'll eat some of those. The other is a cheap generic type that she loves, Meow Mix or Top Kat are her favorites now. The third is a small amount of some canned or soft food that comes with gravy in it.
Her middle bowel is almost always empty by the end of the day, while she barely touches the other two. But she is eating some of the other choices so they are not wasted.
This is one of the challenges of adopting an adult feline, figuring out their favorites without wasting too much money. With a kitten you have a lot of freedom, because they shaped by what they are exposed to.
My advice is to prepare for a lot of experimentation and wasted money, you can't let them starve and they will not like everything you put in front of them. Pay attention to what they rush to when you open the container, and find alternatives that cover their needs best. If all else fails, take them to a vet for an exam and ask the vet for advice.