I’ve gone off coffee for months at a time as a test, but to be honest it’s about the same for me on vs off after the adjustment period.

When I go off, after the headaches, I get good sleep without trying, but so do I on coffee if I have my last one no later than 1pm (where good == 7 hours).

And a proper flat white is so, so good. Therefore I accept my addiction and have two a day!