If you don't want it affecting you too nuch then start slow. Half the caffeine dose daily for a few days, and stop drinking it on days you don't need it (days where you get to sleep in). Then only have it every other day or so. You'll lose your dependence soon enough.
My problem is I love coffee. The process of making it, sitting down and drinking it at home or at a cafe, and everything that goes with it like the dish ware.
I don’t think I could quit cold turkey like you mention. However I wonder if it’s better to switch to tea instead during the reduction period. It might be too easy to drink a second cup if the first cup goes down too quickly…
You could swap in some decaf to sub out 1 or 2 of your normal cups a day. If you drink a lot of it, definitely do not go cold turkey. I did that once and started getting horrible headaches. I’ve cut way back a couple times, switching to green tea but I don’t think I’ve ever been able to cut it out completely, sigh. Went for a good 6 months onky having a few green teas but like the other commenters, as soon as I got really busy and stressed, coffee was back on the menu.
How much coffee are you drinking? You can try reducing the portions so that your routine remains then later reducing the frequency. You could also sub some of the regular with decaf in increasing ratios like 75/25 then 50/50 then 25/75
Your idea of swapping in fractions of decaf is good. I haven't had much luck in the past with decaf, which to me has an inferior taste. Also makes latte art difficult. Could never get a decent crema out of the decaf beans I tried. However, I'm not opposed to trying more decaf varieties.
I guess it depends on the decaffeination method but it might be worth some experimentation to find the right variety.
with any habit change, the less you have to think about it the easier it will be to make the change and to maintain it. Some hard limits can be good and have worked for me like no coffee after 12pm or limit the portion size to 1 espresso or 1 doppio but no more for each serving or only 2 servings per day, etc. I do think that at some level we are fundamentally lazy in the sense that it is easier to do nothing than it is to do something and it is easier to do something small than it is to do something big. That's where smaller portions and adding steps to preparation (like storing the coffee less conveniently or do not grind more than you want at any moment even if you know you'll immediately want more) can add friction to the coffee consumption process but also smaller changes are easier to adapt to and carryforward.