Step one: Document, Document, Document.
Step Two: Did we cover documentation yet?
Step Three: Complain, with documentation, to the apartment management.
Step Four: Document.
Recordings such as video and audio are useful. Just keeping a log of all such interactions can help as well. But, you want to have the documentation to prove your side of things. If things go really sideways and you end up in court, the judge won't give a fuck about what you say, only what you can prove. Be ready to prove your claims. As we say in the DFIR world, "logs or it didn't happen". Then, start complaining to management. And document (keep a written log, you probably won't be able to record) your interactions with management. All logs should include date, time, who you spoke with, what you spoke about and any actions which management said they would take or actions you said you would take. If it's an option, keep your communications with management in email. Both the sending and received emails will be timestamped and the headers will provide a reasonable record showing that the emails were to or from management controlled email servers and addresses. And they log what was talked about quite nicely.
Ultimately, the goal is to move this from being your problem to management's problem. And it's possible that your problem neighbor is also someone else's problem. If management has three tenants all complaining about the same neighbor, they have more impetus to take action against the problem. Of course, this assumes a neutral management, which can be an open question. But, this is likely the least costly way to resolve the issue.
And people wonder why CCTV footage is always low res and grainy. I worked at a site with something north of 100 cameras and a requirement for 30 days storage. Their server room was mostly just racks and racks of hard drive chassis all wired up to the DVR system.