Coffee and caffeine alone aren’t harmful. Lots of evidence to suggest a correlation between better health and longevity among users. The problem is our inability to understand big numbers. This doesn’t mean “drink more coffee good” as our caveman brains want to think.
How much you consume, and when, is what matters. The when doesn’t have anything to do with caffeine really. It’s more about the disruption of your sleep cycle, caused by caffeine.
Save for a very tiny percentage of people(trust me, you’re not in it), anyone drinking coffee within 12 hours of their body’s preferred go to sleep time(not their ego’s or work schedule or home schedule’s sleep time) will experience a negative impact on sleep quality and quantity. It’s just a fact. It’s not up for debate, or like, your opinion, man.
You either view sleep as a foundational part of a happy healthy life, or you don’t. If you do, caffeine within 12 hours of bed time is going to cause you to come up short of your goals. If you don’t, life is short drink it all day long! It most definitely a performance enhancing drug.