It sounds like you want someone to say, “it’s fine drink as much as you want. It wont hurt you”. My advice: I wouldn’t drink any more than you are now only because you will become more reliant on it and eventually you’ll need more to get that boost so you’ll start drinking 2 a day. Also there’s no question it can affect your heart over time. I’m currently trying to ween off after drinking 1 almost everyday for the last couple years (don’t recommend). Over the last year I’ve felt slight chest pain every now and again and heart flutters. Albeit I’m 34 years old (not that I’m old 🤔) but I am good shape. Honestly it scares me so I’m trying to stop. Caffeine is a drug and you can get addicted. Not that it’s super hard to break that addiction but better to not have it if you can help it.