Where are you living - which country?
As a rule of thumb look at the ratio of animal products; should be as high as possible; proteins of course but in fact also fat.
Proteins and fats of vegetary is better then nothing but not so good as animal.
Carbohydrates are almost useless - and even in some degree harmful.
Groceries are more useful then cereals. Rice is probably better then cereals.
So in dryfood many foods have about 30% proteins, even some quality foods. But if the bigger part of the proteins are vegetary the dryfood is of course not good. Like it is common with cheap cat foods.
If most part of that 30% is animal protein - should be OK. (look at what is mentiioned first; is it the animal products or it is vegetary...).
Animal byproducts may actually be quite good as cat food.
Fat should be say 15-20%. Many dryfoods have too little fat, often so little as 10.
Extra E-vitamins is a plus. Extra C-vitamin doesnt hurt, but C-vitamin is in fact dont needed by cats. But C-vitamin is a harmless conservatory.
(for cats being too fat=to thick the solution is not less fat but less carbohydrates!.
Although for the homeless the usual problem is too little fat and nourishment - so at least 15% fat is necessary...)
As a rule of thumb, it is easier to make good wet food than good dry food. So some cheap wet foods are actually quite good having the animal ratio on 80+.
If wet food is possible in your conditions - do take a look.
A try to give an short answer.... Hope it helps some.