I've spent most of my career coding in offices drinking coffee. I have taken many breaks from caffeine for weeks to months at a time. Many aspects of my life improves like sleep, stress, irritability, awareness of surroundings/smelling the roses. One downside is that I seem unable to focus. Eventually I'll start introducing tea, stronger tea, coffee, until I'm back where I started. [I also enjoy coffee, even decaf, but that's a slippery slope.] And the cycle repeats. Having recognized this, I'll sometimes time the phase of this cycle for when I can benefit most from it. Sometimes background music can work, but it's very tricky to find the right music and it's not always the same type that works. Another solution might be if I got lots of regular exercise but I don't have the patience for it--all the while wasting free time tired from an end-of-day caffeine crash.
My case seems much less than yours and I haven't found a steady-state solution either. Coffee might not be your thing. Don't know if there's anything to take away from it but that's all I have.
Yup, I used caffeine and alcohol for years to deal with ADHD symptoms and only got diagnosed recently. Now, I can't even have them, for medical reasons.
Anyway, maybe you have ADHD lol, and caffeine is not a particularly good substance for the condition (not the worst, but it has a bad stress-to-focus ratio, IME, and Drs seemed to confirm this)... maybe it's better than long term nicotine (although in the short term nicotine can be very helpful).
Basically, I'm experiencing the same as you. Without the chems I'm fucked. Btw, stimulant medication won't necessarily disrupt your sleep; it's also not a silver bullet.
My case seems much less than yours and I haven't found a steady-state solution either. Coffee might not be your thing. Don't know if there's anything to take away from it but that's all I have.