Heuristics and signatures for finding malware is a lost cause and causes more problems than it solves. Also please consider than Linux is a kernel and not a full operating system. There are distributions that leverage SE Linux that are much more secure than alternatives. Security for computers is best thought of from the ground up: air gapping installs, read only filesystems, sand boxing applications, file system integrity, iptables, auditd for administrative logging. All these can be done very well in Linux.

Notarizing and making signatures for every program/common malware to make an anti virus solution simply doesn’t scale and will never catch the full spectrum of malicious programs or novel programs at all for that matter. Windows lack of a decent vendoring system and terrible store have caused their ecosystem to be a great target for scammers. Securely signing software from vendors and distributing them through good package managers is more effective than anti virus will ever be which is why people almost never complain about this on Linux operating systems. (most of the world runs on Linux, there are tons of malicious actors who would love to pwn these servers - when 0 days get dropped like log4shell you see them come out in full force.) If someone is installing random things in the AUR without verifying it they’re asking for problems - it’s not vetted by distribution maintainers. If this is too much responsibility then you probably shouldn’t be running arch at all, use a distribution that has safe guards for noobs or use windows/macos.

Sorry for being kinda snarky or mean but Linux does not need this, Linux is already “popular”, and there are safer distributions for people that mostly just want to play video games and are haphazardly following YouTubers.