You don't need to separate them. Oscars are one of the most convenient things to breed ever. Great parents, they will raise the fry to at least 1" in most cases. You just provide microfoods at first, then they are soon big enough to eat crushed HIGH QUALITY food. Not Hikari, not Wardley, not Tetra. Food made of food, not fillers.
In general, they do well fed a range of pellet like you're already doing (good job!). Also include algae wafers at least every other day. Many O's will happily eat blanched vegetables and my first Oscar loved steamed asparagus. Meaty foods are great, too, but are only part of this omnivore's diet. Insects, in all truth, should make up the bulk of most fish's diet. So the more crickets and such the better, just gut-load them first for maximum benefit.
Oscars will eat almost anything and too much of it. It is our job to control how much they eat. One of the worst things to feed an Oscar is excess. Too much food will kill fish. Obesity is real, and Oscars are frequently victims of it.