I know this is an old post but I wanted to contribute something here. If you're going to add unflavored gelatin or protein to your soup, and you're using canned condensed soup, you should mix it into the canned soup first and then mix the soup and the liquid and and stir it well while it's cooking and you can eat it hot, not warm.
If you're going to add protein powder to anything, do it using the slurry method. Take a few tablespoons of the liquid and mix them with your protein powder until they are well blended. You could use a stand blender to make sure that they're mixed, or egg beaters or just a fork that you smash the stuff down with. Then add it back into your remaining dish in small dollops and make sure that they are well dissolved before you add another spoonful. Then like the first soup or whatever, you just stir the heck out of it so it won't stick.