I'm not vegetarian but my wife is, so I eat plenty of veggie food at home. My approach in an outdoor trekking situation would be quite minimalist compared to what I'd do in a kitchen at home.
Soy chunks are good. They are light in weight and will keep for many months as long as they stay dry. You can get them from health food shops or Asian food shops. Don't think of it as "pretend meat", you won't be fooled! Treat it like an ingredient in its own right. It's more like firm tofu than meat. You will need some curry powder or paste to impart some extra flavour to the stew. A chunk of creamed coconut can melt to either add some richness in a stew or can be used to fry something with. It's easy to carry, as it is solid at ambient temperature. A tube of tomato puree and maybe some hot pepper sauce would come in useful too. Cous cous will reconstitute rapidly, add some boiling water, wait a few minutes and that's your carbs sorted. Young nettle plants are the best greens, it's just like spinach when cooked and there's rarely any shortage of these. Young oilseed rape plant leaves are edible, it's closely related to saag.
As for stock, I also find Oxo cubes rather overpowering. Try Marigold Swiss Seasoning powder instead, it's a lot less virulent.
If you simply want to boil water and make a cup-a-soup, try eating it with oatcakes and have some dried apricots for afters. It will fill you up and keep you full, and the soup will warm you up. A pack of pumpkin seeds is also a very good source of protein.