Everyone should think about threats to their data. Cloud backup and laptops better be encrypted, services with open ports be shielded. Linux viruses do exist, especially for android and routers. But also whatever system has an outdated dokuwiki open in the wild is a welcome addition to a botnet. The value of a botnet is in number of infected systems and you don't need root access to mine monero or take part in a ddos on a machine. Linux security is sincerely undervalued. Selinux, the grsec kernel patches, chrootjail, tripwire... do exist, but are a hassle to setup and maintain. The new container options are nice (docker or flatpack) having your webbrowser contained is not a bad idea.
Update your router, your desktop is spoiled for updates. I stop my 1 am ramblings here.
It's not unlimited on PC's. Most mainstream mainboards don't get firmware updates after 2 years. Weakest link in the security chain sets the time.