I don't particularly see any Bumblefoot in the photo, but there is a lot of cracking going on with some necrotic tissue developing on the edges. As of now, it very prone to getting infected since the bacteria from her skin flora, and the surrounding environment can easily invade the tissue. Ducks, are a little like us in the fact that they can develop cracks on their foot when housed on hard, unforgiving environments. The picture below is taken from a human, but you can see the similarity between your photo, and the one below.
As mentioned earlier, housing them on hard/compacted grounds can predispose them to develop this, so you really want to make sure, there run is soft, especially with heavier weight breeds since there is so much weight being applied on the footpads. Since the area is prone to getting infected, it may be suggested that you continue to soak the feet in Epsom salt water, apply ointment and bandage. How you apply the bandage is really important. You don't want to just use a thin layer of vet wrap, you want to have plenty of cushioning underneath.
Some folks use gauze, or as an alternative, you can cut in a pool noodle, and use that. Continue that process until you see improvment.
I think your doing good, just make sure you keep it nice and clean because the last thing we want is infection. Don’t worry my Pekin ducks got this once and recovered. Very common with heavyweight ducks.