@noblehead beat me to it! I was just going to say that many of those processed quick cook oat cereals get absorbed quickly.
There's no need to go low carb for breakfast if you don't want to. Cereal can work as long as you choose types that work for you and bolus enough in advance. I eat a mix of good quality granola, All Bran, Shreddies, etc mixed with some seeds and I have it with full fat milk. I always, always weigh my cereal and that means I'm sure im having the same amount. Doing it by eye is inaccurate. It's a matter of experimenting with the cereals to see what suits you. As an example, for me Shredded Wheat can cause a spike even though in theory it looks a healthier option than granola. Anything with some fibre and fat mixed in can help too, so bran or similar, grated coconut, seeds, whole milk, etc
Other carb options are toast and eggs/cheese/veg. Again, find a bread that works for you. I like rye bread.
I also have a croissant with ham and melted cheese in.
Another thing I do is eat as soon as I get up. If I delay breakfast, I find my Dawn Phenomenon kicks off and puts my blood sugar up very quickly. If I have to delay, I either eat something small and bolus, or have a tiny amount of insulin and no food.