One never follows science but nature. Science is an enterprise and dogmatic control mechanism - the scientific method is sound... it's institution not so much.
Only the basics are healthy if they're free of environmental poison and roasted beans are not basics... they're stimulants.
If you enjoy coffee, drink as much as you can but do not expect it to be healthy - it's stress on your system.
In hospitals they often allow coffee even if the patient has heart trouble such as was my case, they follow the "science" I guess. I think certain health benefits of coffee don't appear to occur with decaf iirc. It's said coffee is the main source of beneficial antioxidants for most. The stimulant aspect is connected to the anti-alzheimers effect, dopamine stimulation and so on (same with nicotine.) Stimulants should mechanistically induce insulin resistance, but the opposite happens with coffee. Also it's a liver protectant. Just a little contrarian push back

I always said here how caffeine is such a dirty stimulant, by dirty it means you get a lot of unwanted sides with stimulation, certain amps and ephedrine feels "cleaner" IME. But these 300-400mg PWOs are scams and probably unhealthy; I did read somewhere Starbucks has a 600mg coffee!