For ages now, Linux has been relatively virus free because let's be honest, Linux is either used by just a few nerds (who are often just a tad harder to trick than the tech illiterate) or by servers, for which entirely different classes of malware exists.
With effectively no antivirus protection, either because of a lack of options or because the outdated mantra that "you don't need it" because of some peculiarities that Apple used for years to deny the existence of macOS malware, Linux users are bound to run into viruses sooner rather than later. Hackers that are after Steam accounts will definitely try their hardest to infect Linux desktop users.
My best hope is that the way Linux distributions are woefully incompatible with each other will protect the hardcore Linux users somewhat from the viruses that will inevitably be spread across the "common" Linux environment. I'm sure we'll see Flatpak/Snap viruses down the line, but for a short while, we'll hopefully still have time to see where the Linux landscape is headed.
The same idea came for apple and google, and their software stores, but google mostly fucked it up by allowing a "flashlight app" to access your contacts and gps location, and apple fucked up by not allowing you to sideload a program at all, even when you know what you're doing and trust the software.
You can't run Office on Linux, of course, but there are plenty of scripts you can download to set up a VM and do some remote desktop trickery (I've just recently gotten cassowary running on my laptop for exactly this use case).
It's the small touches like these that are the problem. Linux on the desktop, and especially Arch based Linux as is running on the Deck, eventually needs some kind of shell script to work around some kind of issue or lacking feature that people have come to expect from Windows.
Hell, even the "official" software stores will eventually become polluted because let's be honest, nobody guards Flatpak against malware and promising to make games run faster combined with a YouTube/Tiktok campaign will probably get enough installs to get plenty of hacked Steam accounts.
I've never seen an offering for Linux AV that doesn't require some kind of endpoint server setup. Most Linux viruses attack servers, and those seem to be the target of the Linux AV industry. ClamAV exists, but that's probably all you can say about that, it's not exactly difficult to evade.
Regarding Flatpak (which I wish success) and Steam (which already has a lot success) I'm feeling more worried. They want grow and add stuff but actually must be a reliable source.
I'm just glad that Microsoft eventually decided to bring antivirus in-house, and I don't ever again have to mess with 3rd-party security products for my Windows box
I wonder though if Microsoft Defender ATP and Virtualization-Based Security makes it more difficult.
Sure, if someone gets root on my Linux PC, they could do a lot of damage. But my most important things are parked in my home folder, which any old script running as my user can access without any problem. No need for privilege escalation or other fancy things.
AppArmor and SELinux can probably mitigate this, but I don't think they see particular widespread use in "default deny" mode.