Oh that’s hard. I hate, hate, hate those mixes. Would do bone broth for some meals, fruit and yogurt smoothies for others, and definitely throw some nut butter (cashew, almond, whatever) into the smoothie.

Date shakes are good, lots of sugar but fiber and nutrition.

And if you can tolerate soup - a can of cannelini beans, a can of butternut squash puree, and some chicken or vegetable broth, with salt and whatever else you want, is so easy, delicious and again does have fiber. Just heat them together then blend with a stick blender.