I don’t think a Linux anti virus program would be such a big security win. Phishing is the biggest security threat to most users, and no amount of software can prevent that.

Sure, downloading and running random shit is a concern, but people in that group are a bit of a lost cause. The best solution for that is to harden the OS, prevent running executables through the GUI, or from user folders (I think SELinux could do that), disable sudo on the user account, and only allow installing Flatpaks. The security of Flathub may not be perfect, but it’s a smaller attack surface than the whole internet.

But even if you do that, an Indian call center scam is still going to manipulate your grandma into buying Amazon gift cards, so… It’s a lost cause.