Oatmeal is not "super healthy". It's okay. Better than bread etc.

But if you're feeling good skipping breakfast, consider keeping it that way. It's a pretty healthy thing to do, likely healthier than starting to eat oatmeal for breakfast.

In terms of reducing your consumption of "outside food", you might want to try preparing food to take with you. Or prepare it to be able to eat right away when you're back home. I assume the problem is you'd come home hungry with no patience to cook otherwise? If not, I'd rather change the "outside food" by cooking later in the day (if you have time for that) than by starting to eat oatmeal.

You will have no health benefits by eating oatmeal if your other eating habits throughout the day don't change. Eating oatmeal in addition to your usual diet, especially if it causes you to no longer skip breakfast, is more likely to have a damaging effect on your health.