I've been off six weeks and feeling pretty decent. I'm not feeling as good as I did on caffeine but better than I did at this point last time I quit, which I attribute to TRT.
The physical withdrawal symptoms resolve pretty quickly but the mental symptoms, including low mood, difficulty concentrating, lack of motivation, anxiety, etc can persist for many months. I've seen many reports that it took a year or longer for full recovery.
The idea that it could take over a year to recover from a caffeine habit is completely foreign to most people. Typically, people try quitting, discover they still feel crappy after the 1-2 weeks they were told withdrawal is supposed to take, conclude they must require caffeine to feel good, and start again. People spend entire lifetimes on it for this reason. The longest I've made it in the past was about four months before falling off the wagon due to this sort of thinking.
I should probably start a new thread about this but mendelian randomization studies suggest the only real benefits of coffee drinking are reduced risk of gallstones and kidney stones. The rest of the purported benefits are a mirage of associations that aren't causal. What it does do is shrink your gray matter volume and increase your risk of osteoarthritis among other harms.
So, I would encourage you to remain caffeine-free after making it this far. Check out the decaf subreddit for inspiration and countless examples of year+ long recoveries:
www.reddit.com