My favourite anti-virus strategy is "not being a muppet". Don't run software whose provenance is unknown, don't click on random hyperlinks, disable autorun and the fetching of external embeds in emails, etc. This has the advantage of being very efficient in terms of machine resources and does not require regular updates.
Sadly it seems to be beyond most non-technical types, and a good few techies too.
Alas, for work purposes Windows with an "approved" AV is required to connect to the VPN. To my surprise, does the job while being fairly lightweight.