Not sure if that's a thing in France, but alternatively to plant milk for lactose intolerant
- Lactose-free milk (there are versions with lactose removed instead of broken down, that aren't sweet and taste basically the same as normal milk)
- Lactase enzyme taken together with the coffee, to break lactose down
I don't really see plant milk as the lactose-intolerant variant, but a vegan option, but that might just be due to the fact Finland has lactose-free milk available as an option basically everywhere as milk is such an important part of the coffee culture.
If you decide to do that I recommend taking the battery out first, if the phone can boot without it. Phones have a tendency of mismanaging their batteries to the extent they turn into spicy pillows relatively quickly, if you just leave it plugged in and use it remotely.
My main source for this is an LTT rant from back in the day, but I don't really have a reason to not believe that based on experience.