This is really filthy. From the perspective of feng shui and hygiene, it is easy to make people at home sick.
Fortunately, the location of the balcony of life is not big, but there will be no serious illness. However, minor illnesses should be inevitable, and the problems mainly appear in feet, liver and gallbladder.
You also mentioned that your neighbor is savage and fierce. If you seal it hard, or fight feng shui with him, you are likely to lose both sides, and no one will come to a good end. Feng shui was not created to fight and hurt each other.
If possible, I would suggest that you put some potted plants and plants on the life balcony, because they should be used to ward off evil spirits and absorb these filth. Try to choose tall ones, and it is best to choose some ones with strong vitality, such as those with many leaves and sharp ones. If you find that plants can't feed, you'd better continue to replace them.
That's all. I hope I can help you. I hope you live comfortably.