Correct. You should be keeping regularly updated offsite backups of any and all important files if you are self-hosting your own files instead of storing them with a cloud provider like Google.

By media I just mean things like movies, TV shows, and my own family photos and videos.

Most of those media files exist on other devices, too. For instance, Our family photos exist on the devices where the photos were taken + my home server, and before we delete them from our other devices, we make a backup of the home server.