When the bananas have brown spots in the skin they have more enzymes (good for digestion), also when they ripe their complex sugars become single sugars (monosaccharides). The body can easily absorb monosaccharides, they don’t even need to be digested. May be that’s the reason why even celiacs tolerate ripe bananas.
Also bananas tend to cool you, but I noticed I can change that quality by frying then a bit with butter or ghee in the pan. So I can eat them even in winter.
I really like bananas and am also a vata type. I’ve been eating an average of 3 to 5 bananas per day, every day, in the last 2 years, mostly for breakfast with butter and almonds. But they were always ripe.
I cannot report any problem so far except when I use too much butter, then I noticed some heaviness.