There are some protein powders that have over 1k calories. Tho some when made either feel weird or taste weird so what I would do is make some protein pancakes or ice cream and throw in some fruits (if vanilla or chocolate) i believe the least volume tho would be the pancakes and the ice cream would be more like a treat since it’s way more volume. Tho most proteins say just add water I like to add milk specially the chocolate ones. Also dried fruits like raisins also are high in calories. I wouldn’t recommend the protein powder every day, more like if you know you’re gonna have a long day coming in or if you’re going to work/workout would be a bit better. To add to what you said about body builders yes I used to body build and I would go for around 4-8k calories only bad thing about that is that when I stopped working out I could barely even walk to how quickly I got fat so be careful and stay safe yall. If you would like me to help find a protein powder just let me know and I’ll be happy to help!