I’ve beaten coffee addiction 4 times in my life. Gone clean for weeks or months thereafter. (There may have been one time I did more than a year?) Note that I am presently back on it.
For me it’s an on/off thing. A halfway state where I enjoy the occasional coffee is hard. It’s enjoyable as when you’re in this state 1 coffee gives you a noticeable buzz (!) but somehow I always keep enjoying it too much and ending up back on the hook.
I’m not a fasting expert (literally just on my first multi-day water fast right now) so take my advice with a grain of salt… But I think if you want to try this out you would definitely want to kick the caffeine addiction first and then fast once that is totally behind you. Coming off caffeine is actually pretty tough for a few days. (I suggest slowly ramp down usage for 7 days then go cold turkey, and even then you can expect to have a rough 3-7 day period.)
From the sounds of it the coffee is not worth it for you. I am the opposite - before I have my coffee each day I am scrambled, but it helps me focus thereafter. It saved my life today - I woke up feeling fresh after 38hrs of fasting but within a few hrs I felt a bit off. That first coffee settled me right back down and the day has been pretty easy since.
I kicked my coffee/caffeine habit pretty quickly. I was so proud. Bragging to everyone. Well about after 2 weeks I noticed I was exhausted around 2 ‘o’clock in the afternoon. Since I only drank one cup in the morning I didn’t even think that this was the problem. So I started again having my one cup a day. Black of course. My afternoon fog lifted as soon as I started again. Lesson learned. Now I drink it a little bit later in the day instead of when I first wake up.