Same journey for me, sadly I don't think drinking coffee consistently is the perfect answer. No matter what amount I drink it either becomes too little (because I adapt) or too much (Far worse sleep, somewhat depressive, can't work out or jog anymore because of heart fluttering, only truly feel good for ~4-5h per day, then worse all day). I think the only theoretical way to consistently get value out of coffee is to drink it during the work week and then force myself to withdraw on the weekend so my body always has a fresh response to it. The reason why I don't like this either is because I obviously lose two entire days of my life to feeling pretty bad per week and you still eventually start drinking more because it's inevitable. Now what I remember seeing over the years is that whenever somebody would mention that they don't drink coffee and that person is still a high performer then they always seemed to be really into fitness and sports. Maybe this is the only way, using physical exercise as a stimulant instead of coffee.