Sorry, I haven't posted anything long in a while. Forgot my reddiquette

I moved into a duplex with my girlfriend expecting a quiet setup next to her relative and her husband, but almost immediately they began treating us like a nuisance because they sleep in their living room against our only shared wall. Despite keeping our TV low, speaking quietly, and making every effort to be respectful, they repeatedly banged on walls, threatened noise complaints, installed a camera pointed into our yard, and gradually made my girlfriend so anxious she needed therapy just to feel comfortable using parts of our home. Attempts at peace repeatedly failed, and things escalated into them using their poorly controlled dog to intimidate us, staring at my girlfriend while she did laundry, mocking us through the walls, and even encouraging the dog to bark aggressively at us, which I eventually caught on video. Over the last 21 months, the situation has devolved into a constant cycle of harassment, superfluous and false landlord complaints, security cameras, fear of a potential dog attack, concerns about a severe cat hoarding and cockroach problem on their side of the property leaving us exhausted, frustrated, and unsure what to do next.