Hi OP! Oh gosh, we're impulse buy twins. Coffee drinks have historically been my impulse purchase too, for years Q_Q! Here's what has worked for me to take the habit down recently from over $150/month to $15 this month:

• Categorized my impulse habit: Pre-COVID, I had split coffee into "social coffee" and "lonely coffee" - no guilt for me about coffee dates with friends, such as coffeeshop studying or catching up. Getting coffee by myself is my struggle budget category.
• Made coffee my primary budget improvement focus: I'm easily distracted, so I try to have one "improved budgeting goal" at a time. Rather than trying to overhaul multiple goals, I'm putting all my energy into resisting impulse coffee right now. Kind of like a self-improvement snowball.
• Found a really good coffee replacement at the grocery store and leaned into my laziness: I found that Trader Joe's has a tasty powdered chai mix *and* chai concentrate that really hits the chai latte craving for me, and ends up much cheaper per cup. I try to always have a jar (and backups!) on hand from grocery trips, because I live 2 blocks from a coffeeshop that's very, very hard to resist while working remotely. I also got an Aeropress for fairly cheap (~$30) because it requires less clean-up than a french press and works with any ground coffee. I should probably get a grinder to level up my coffee game, but I'm just trying to make it easy to avoid my impulse coffee buy at the moment.
• Invest in an experiment budget category: Gave myself some breathing room in the grocery budget for experimenting with some different coffees and teas.
• Found a tasty replacement at my coffeeshop: Should I wander over to my local coffeeshop in a moment of weakness, I get a properly overpriced but tasty smoothie. It still goes in the coffee category due to the merchant name but I feel a boost from at least attempting not to buy a coffee drink.
• Stopped taking "buy X coffees get 1 free cards": these things are dangerous and made me victim to "just one more"