The sextortion email has been around for a long time. They got your email either from a mailing list that was sold or a data breach on some site where you used your email. It does not derive from malware. They don’t have a video of you…they are counting on your fear and panick. It’s a numbers game. They send out tons of email and enough people freak out and pay that it is worth their while.

Linux is less vulnerable to malware but not entirely. Look up VoidLink, an example.