I have just decided on a whim that I no longer want to support the dairy industry and cut it out of my diet cold turkey. I've already trialed a run and I felt great but it was so difficult. Never realized how much dairy was in my diet in basically everything I ate and it wasn't long before I ran out of things to eat that didn't contain it. Even subjected myself to eating cereal with water which was extremely unpleasant. It's been hard but I know you're the community to ask for help because you've probably went through this sort of thing before.
Get oatmilk and get used to reading the ingredient list on everything you buy. Chip brands use dairy to bind flavor to the chip so you can’t have most barbecue chip brands now. Luckily you picked something that’s a common enough allergen that in the US they have to list it in bold at the very bottom of the ingredient list so you can check it quicker. At this point in time being lactose intolerant has been in the mainstream long enough that there’s a ton of dairy free alternatives. Once you get used to it you won’t even notice anymore, the only pain is having to ask if dishes in restaurants are prepared with butter because like 90% of the time they are but it’s an easy sub so just get in the habit of asking