I only back up things that would make me sad if I lost it or cause me a lot of time-sensitive work. Personal data files and configuration files. Media? I wouldn’t sweat it if my media drive got corrupted by malware or a hack or a lightning strike. I’d just live with a smaller library until I get things re-download again. And I’d be ok if I can’t find a handful of the rarer things. Pictures of my family? Backed up locally and on a remote server with immutable backups. Configuration files? Synced with a remote git repository.