Oatmeal, Good of Not Good for T2's?

I have type 2, A1C bounces between 7 and 8+ depending on how good or bad I am eating.

My Doctor gave me a handful of the Dexcom G7 devices to try. They seem to be a great diagnostic/learning tool, I'm discovering things I didn't know about eating.

My point today is about Oatmeal. There's all kinds of posted information about how it is a good food for T2's, even on this forum. My experience based on these Dexcom devices is that Oatmeal is not a good food for T2's.

I get the stuff in the big tub, it is not instant, it is not flavored, contains nothing but whole grain rolled oats. I put Cinnamon on it to flavor and sweeten, a little milk or half/half, that's it.

My fasting glucose was 171 when I ate breakfast, two hours later it was 218 and in the middle it peaked to about 250.

Assuming I have understood what I've read about T2 diabetes and these CGM devices, those oatmeal numbers do not look good to me.

I understand the water and fiber benefits of oatmeal. I understand how it is better than a trip to the waffle house, but from a blood sugar perspective I don't see how it is a reasonable food.

My same claim goes for grape nuts. That is documented to be T2 friendly but acts almost the same as oatmeal for me.

Am I misinterpreting the CGM? Is this device showing me more than I really need to care about? Is oatmeal really what it is documented to be?