A Larger Heart
Having a large heart , especially in proportion to the giant, would counteract any negative affect associated with blood flow, hormone circulation, and lack of oxygen to the brain
Larger hormone production centers
Such as the thyroid, testes, thymus, pituitary, and adrenal glands , to increase the amount of the hormone in proportion to the body, and it may fix your puberty & menstrual issues
Thicker Bones
This will not only increase bodily support , but also ramp up the production of red blood cells. This may also solve your deafness and insomnia problem by making the bones in the inner ear more sturdy , and increasing the amount of oxygen that gets to the brain
Stronger Tendons / More Skeletal Muscle
To allow the giants to move their added skeletal weight & the added weight in general due to the square-cube law
Larger Cerebellum
Increases coordination proportionately to the larger body
More Mitochondria
Since the muscles will have to do a disproportionately large amount of work , the added mitochondria will be able to compensate
More Capillaries
Especially near the surface of the skin , to increase effective temperature regulation, ( which many other large mammals have issues with ) which fixes the sweating problem
Everything else can be scaled up normally , except for the cerebral cortex, as that might have the side affect of increased intelligence, that is , above that of the average human , but hey , if that's your intended effect , knock yourself out