Chop up ham, carrots, celery, green peppers to 1/4" chunks. Sprinkle veg with salt to help extract moisture. Dehydrate them. I would do this at 160f or above for pathogen lethality and come caramelization.
Per USFDA, A water activity below 0.85 is safe for shelf stable as no foodborne illness grows. Molds that are safe can grow down to Aw 0.7. There are charts to guesstimate Aw from % weightloss if you don't have a $600 Aw meter. But think of dry jerky as an example.
A good stew, 1L serves 2, approx 4c:
Dry powdered Bouillon for 1L
Dehyd. Ham, carrots, celery etc as desired
2 packages ramen
2 packs of the ramen seasonings
3T potato starch, NOT dried potatoes!
Add 1L boiling water, stir.
The potato starch will thicken nicely at these temps without boiling to a clear look like corn starch.
All rest will rehydrate.
Shelf stability comes from ensuring sufficient dryness. Lowering pH with citric acid massively increases shelf stability, think of Sinigong soups or Thai hot and sour soups, if you like those.