DH has had Type 2 diabetes for years, which he controls very well with diet and prescription medicines, and his readings are very good.
Every diabetic is different, and what works for one in terms of diet may not be right for another.
We eat more or less the same ( lots of veg, only lean meat, fish, etc, some carbs but avoid sugar) except that DH eats biscuits which I don’t. I eat some fruit which he doesn’t, yet guess which of us finds it hard to shift excess weight.
As you are not overweight, it sounds like yours is genetic, OP, so take advice and see what works for you. It is not something to worry about at this stage.