I’m not a coffee drinker, but I did recently get told by doctors that I’m lactose intolerant and have mostly cut out regular milk from my diet.

I went from taking milk with my tea to having tea black. Took a couple of weeks to get used to it, but I no longer miss the milk.

For cereal, I went with lactose free milk. I hated it at first, but forced myself through it for a while. I think by the time I was 2 L through I had mostly come to “accept” it, but after about 12 L or so I got to the point where I no longer noticed how sweet it is.

Either of these, or both of them (use LF milk but much less than you’re used to), could be viable options for your coffee. It’s about giving it time to see if you can adapt.

Another option which I personally never tried is to go with plant-based milk substitutes. Soy, oat, almond, cashew, pea, etc. This video presents some facts about each as well as an entirely unscientific small-scale (at least 7 people, very likely 9, probably not much more than that) taste test. Their results said that soy is probably the best option, being the cheapest (at least in the US, where they did their test), and 2nd best both for nutritional value and in their taste test. It was also the best for foaming/frothing, which I gather might be important in coffee? Oat came second, winning both taste and foam, but being less nutritional and pricier.

If environmental impact is a factor for you, oat is probably best. Almond emits less carbon, but also uses by far the most water of any dairy substitute, while oat is 2nd best in carbon and also 2nd best (with a huge gap to 3rd place) in water use. With how important water scarcity is in Australia, I figure that makes oat the winner here.