I'm not sure if this will help or not, but I uninstalled VLC and installed the M1 version. I closed and restarted OBS and it didn't fix anything. Then I uninstalled and installed VLC to the Universal Binary version, and after restarting OBS the VLC sources in my project started working again. I'm not sure if it's coincidence or the binary type, but it seems to be working now on the VLC universal binary. By the way, I use AppTrap which removes plists and stuff when I delete the app, so you might need something similar to get rid of the prior settings for VLC.