If chlorogenic acid starts in it' highest concentration in the green bean, shouldn't the healthiest coffee be the lightest?Updated a month ago

No, that’s a reductionist view of coffee. The health benefits imparted by coffee are a sum of its parts. Some compounds, like melanoidins for example, are formed during the roasting process and they have anti-inflammatory effects and are beneficial for the gut. They peak at around a medium roast so you’d miss out on them if you roast too lightly.