Since the nuget package VideoLAN.LibVLC.Mac doesn't contain a build for arm64 (as of version 3.1.3.1), if you want sound or video for .net applications on Mac M1, you need to import LibVLC yourself.  Luckily, the latest build of VLC contains everything you need.

Navigate inside VLC.app to the Contents/MacOS folder.  You can copy the needed files into a lib folder with your compiled app in the exact structure as seen in the screenshot.