Protection for older iMac, if and when Apple ceases support

I have used Intego Netbarrier and VirusBarrier for many years on my iMac as well as always installing the latest security updates from Apple. I'm running Catalina 10.15.7 on my iMac 21.5 inch - Late 2013. There are rumours circulating that apple will abandon support/updates for my iMac by the end of this year. If so, I would find this very irritating, as I have a 500GB SSD installed and the system runs fast and efficiently.

I asked Intego if their software could satisfactorily protect my iMac, if and when Apple were to stop providing security updates. Intego were very confident that their software would provide complete protection as follows: 'VirusBarrier will provide complete protection and security even on Macs stuck on older macOS that can no longer update to the latest macOS that offer security updates. This includes older Mac OS X and macOS like OS X 10.10 (Yosemite), OS X 10.11 (El Capitan), macOS 10.12 (Sierra), and macOS 10.13 (High Sierra)'. I keep reading that Mac OS 'doesn't get viruses' - this is news to me as I have had two malware infections over the years, both of which were Quarantined and deleted by my Intego security software. It's a bit strange that some who maintain Mac viruses don't exist, often proceed to advise on actions to take if you get one. I have to say that Intego Support have been fast and reassuring whenever I have had an issue, so I'm inclined to trust them based on my own experience. I have all Apple devices - iPhone, iPad and iMac and I love the way they can seamlessly share my data - I really don't want to lose my desktop from my private network.

So, would any other community members be prepared to trust Antivirus/Security software to protect an unsupported Mac OS - or do we just keep buying new hardware?