Hence why we can estimate Daily Recommended Intake; for example this nutritional profile https://www.completefoods.co/diy/nutrient-profiles/51e4e6ca7... which would give you the mix of vitamins and minerals and carbs and fats you need.
From there, you can mix up your ingredients sourced from https://www.completefoods.co/diy/ingredients or buy it from a company https://soylent.com/products/powder-original (not affiliated but I have bought some at one point.)
Now, you can tell me it's "not real food". It's a No True Scotsman fallacy, but if anything, sure. I agree. It's not a burger. But it is edible and it will sustain you for possibly weeks to months. A few people on the internet said they've done it.
I've eaten Soylent. It's ok. Can't say I'd want to eat it every day of my life but I have had moments where I was busy or not interested in cooking -- and then, for those cases, I imagine a carefully engineered Soylent will give you a more balanced diet than the Taco Bell I got in a hurry because I was hungry and didn't have time / want to cook.
Now if you think scientists who spent a decade or more of their life studying nutrition either for a civilian or military purpose are morons, then fine, have that opinion.
But I think processed food is a nicer option to have than no food, if I needed to feed my family and had very little money. Soylent clocks in at $1.82/meal. Now I won't deny you might be able to make beans and rice for cheaper than that, but Soylent looks like a nice, balanced, cost-effective option compared to spending $20 at a restaurant.