I wasn’t a big oatmeal guy until I realized you don’t actually have to go sweet with your toppings. What I like to do sometimes is avocado, a fried egg, black pepper, and then some sort of salt. I’ve done soy sauce and even hoisin, or shark brand sriracha. Sometimes even those oil-marinated artichoke hearts from a jar.
See also: mushrooms, cheese, onions & garlic. Fried pieces of whatever cured pork is to hand, especially if you're having an egg in it. Flakes of smoked fish also work well alone or with egg - fling in some chives & chillies for zing & colour.
Tbh though, a bit of salt was the traditional Scottish way of having oatmeal, with black pepper making an appearance once spices became widely available.