Does this really fill you up? DIY concerns

Im looking into this whole soylent thing (i ordered some from amazon which should be here tomorrow). I like the idea, and have been looking at the DIY portion. Thing is, as someone focusing on a high protein low calorie diet (which standard soylent isnt), I started looking at recipes and playing around. And I came to the conclusion that if I mix up some whey protein, a little oat flour, a bit of oil, some psyllium husk, and some vitamins/minerals, I can have a complete "diet". Sounds cool...except when I break my needs down into 1 400 calorie meal, the calories come from 48g whey (1.5 scoops), 20g oat flour, 10g canola oil, and 10g husk. This does not seem like its gonna hold me over (hunger wise) for more than a couple minutes??? Am I missing something? Anyone do DIY and have any pointers?

Edit: Which brings me to an even simpler idea....If I wanted to try ketosis, could I basically just mix some whey with some cream and add some fiber and nutrients? Doesnt keto help fight hunger anyway so it would be easier to adjust for a sustained period? Im just brainstorming now, but Im in the process of a much needed weight loss journey, and while I have been and know I can sustain a regular diet, I spend way too much time thinking about and planning meals, which is what drew me to the whole soylent thing to begin with. I just want to go on cruise control till I get to a healthy weight and can start bulk/cut cycles. And now im rambling. Good night!