OBS has a recording button. See the article below for tests with the THETA S. The same process should work with the THETA V. Make sure you test this prior to your event with a short clip.
Are you using a Mac or Windows? If you’re using Windows, search through this forum for information on THETA V live streaming from Windows. The audio will be single channel from the camera, though you can mix a separate audio channel.
On the THETA V, you may need to change the audio and video bitrate.