If you REALLY need it, I’ve seen some people recommend ClamAV but really, I don’t like the concept of antiviruses. They run with I’m assuming full access to your storage and generally bog down your system performance. IMO, the best line of defense for your system is you. Use your common sense, stray clear of the shady websites, stick to well known and safe recommendations (especially relevant since you sail the high seas) and don’t run random commands from the internet.