I make a huge bowl of cereal with milk every morning. With brown sugar, raisins and/or mashed-bananas thrown in.
I have never had trouble with boiling milk. I have always drunk boiled milk since as a kid. I don't think boiling the cereal in water first is helpful. That would dilute and bland the milky taste of the boiled cereal. Unless that is the intention.
Characterise the microwave
Every time I get to use another microwave oven, it would take me a few days to "characterize" the microwave oven. "Characterization" is an engineering statistical practice of observing the behaviour of a system in order to effectively use that system.
Characterizing a microwave behaviour is a much simpler affair than industrial systems characterisation.
In the case of making cereal with milk, characterising the timing and power levels that would churn the cereal but prevent it from spilling is a very satisfying experience.
As I do not use processed oats, I have to bring it to a boil and then let the bowl of cereals sit for half an hour for the oat soften and almost dissolve. Since usually, morning is such a rush, I have decided to microwave the bowl of cereals at night before I go to sleep so that I simply need to warm the bowl of cereals up in the morning. I set and start the microwave and walk away to do other things - perfect each time.
Or use a slow cooker
But then, of course, you could invest in a cheap little slow cooker and start the cooking at night. I am thinking that the highest heat setting should be used, so that the bubbling would churn the concoction to prevent lumping of milk.
In the morning, you would have a nice warm pot of cereals where the oat has dissolved into the milk. Turn the power to the lowest or off. though you might still have to stir it to even out the distribution.
Then slice in bananas, throw in raisins or lychees and let them sit in there for 10 minutes. Then serve with sliced apples or apple sauce or cinnamon or have a super supreme of every thing.
You should reuse the pot for the next morning's cereal without needing to wash it - provided you do not introduce bacteria by directly eating from the pot. Just wash the clay pot once/twice a week. With the current state of the planet, we seriously need to reduce our water usage and avoid obsessive compulsive washing.