Linux antivirus is more about preventing viruses from propagating to Windows machines via email etc.

ClamAV and ClamWin (frontend for windows) are FOSS software, however do note that Clam does not offer real-time protection. For Linux it does offer On-Access scanning, this additionally needs to be setup. I am unaware if the current Windows version(s) has changed this.

https://www.clamav.net/

It’s called “running Linux”