I have no issues with dairy so will go full fat in everythingYou asked about milk,
It all depends on which milk, full fat, semi skimmed and so on.
Milk contains lactose, a sugar, which turns to glucose rapidly, the less fat in it, so if you have full fat the less sugars, carbs. The slower the spike. Because the natural fat slows digestion.
The less spike you will get, but it is also dependent on how you tolerate dairy of course!