It sounds like you’re looking for intrusion detection or prevention rather than antivirus.
Great list here https://github.com/sbilly/awesome-security#ids--ips--host-ids--host-ips
However it’s likely that these do not run on asuswrt-merlin out of the box and may require additional setup or hardware.
You may even be good enough by using the built in firewall on the router interface and making sure no ports are open/forwarded.
But, why?
ClamAV is a scanning engine that uses a database and heuristics to detect an infection.
Are you looking for an Anti Virus Scanner, or Intrusion Prevention System?
It sounds like you’re looking for intrusion detection or prevention rather than antivirus.
Great list here https://github.com/sbilly/awesome-security#ids--ips--host-ids--host-ips
However it’s likely that these do not run on asuswrt-merlin out of the box and may require additional setup or hardware.
You may even be good enough by using the built in firewall on the router interface and making sure no ports are open/forwarded.