I also recommend switching from coffee to tea if you consume a lot of it. I used to drink gallons of coffee a day. Basically from late highschool to a few years into my career (so like 10 years), I didn't drink anything but coffee (with milk). No water, even at night I was drinking coffee. I quit cold turkey a few times and I basically passed out for a few days from the headaches and feeling dizzy. When I quit I would sleep like 16 hours a day for a couple of days and in a weird way it felt great because I wouldn't be conscious for the worst of the withdrawal symptoms.

As I got older it became clear that this was probably both unhealthy and unsustainable so I switched to drinking black tea (with milk) all day instead. I make a giant batch every few days. I feel much better now and the headaches are not nearly as bad in the morning, I just feel slightly tired if I don't drink tea. I may have undiagnosed ADHD or something because I basically can't concentrate without a stimulant (this was true even before I started drinking coffee), but once I take it I find it much easier to focus. I also drink matcha sometimes, but don't like the taste as much. There's something about the bitter taste of strong tea or coffee plus milk to smooth it out that is irresistible to my brain.