Honestly, the last pictures there make it look awfully good! I’m a human ICU nurse, and have pretty extensive experience with wounds, both traumatic injury and things like pressure sores. I absolutely 100% agree with not closing this wound over with any dressings at this point, unless you can’t keep it clean. (We generally cover open wounds to keep them clean, protect them from secondary injury, or to manage exudate. It’s never to “seal” them closed.) Irrigating with saline to clean it out regularly is a much better idea. The last thing you want is for it to close over on the surface and create a pocket or abscess. This wound needs to drain, and needs to heal from the base on up. If you are having trouble managing the drainage, coat the surrounding skin with a layer of cream or Vaseline to protect the skin. Don’t put caustic things into the wound, and use saline flushes and mechanical scrubbing to clean it. Vashe (https://www.urgomedical.us/products/vashe) or something similar would be excellent as well, if you can get your hands on it. The smell could just be the serum and goo, rather than true infection, especially since you covered your bases well initially. Flamazine (silver sulphadiazine) would be wonderful in that wound for protection, keeping it soft, and promoting healing.
Time and cleanliness are your biggest tools here. Keep at it, and don’t get discouraged if it takes a bit. At least you don’t have to worry about flies in there too this time of year! Once the wound heals from the bottom up, granulates in and has new skin over it, keeping the skin moisturized and supple will be best for minimizing scarring. Don’t worry about that yet though, just keep it clean and let it granulate from the bottom up.