I usually work around it by saying “have”. “I’m going to have some Soylent.” “I had Soylent today at lunch.” Once in a while if I’m feeling fancy, I’ll say “consume”.
“Eat” sounds wrong, Soylent’s not solid.
“Drink” I avoid only because it conjures ideas that I’m not actually having a meal.
I need a spoon for both soup and yogurt. I’ve never had a yogurt that was liquid enough to not use a spoon. I know there are 100% liquid soups, but I never eat soup that doesn’t have something solid in it.