Antivirus is completely unnecessary and terrible on windows and linux... and on linux it's uniquely useless. Everything is installed from a centralized repo, antiviruses won't be of any help at all. antiviruses came about because windows let executables just be run easily and simply and used them as the default way of installing software, this was beyond idiotic and the reason that OS became infested with malware. Linux never made that mistake from the start, and so antivirus is unnecessary.
On windows you install things from random websites as the primary method of installing stuff, this means anything can install anything and has installers that can install bonus stuff. This is why windows has so much malware.
On linux, imagine your distro is an app store, ubuntu is an app store, mint is an app store, fedora is an app store. The apps themselves can't manage installation so they can't bundle nonsense with them. you just click install and you get only the thing you wanted and nothing else.
Since your distro curates all the software, as long as you trust your distro, you'll know there's no malware on your computer, because you get all your software from the distro (or flathub but same idea).
It's true for any variation of Linux. Hell, the vulnerability (Mimikatz) that was crucial in the most expensive cyber security attack in history is still there in Windows.
And for X11 to be exploited you would need to get and run malicious code in the first place. The Linux security model kicks in before you get to that point.
all you have to do is trick the user into installing something malicious, and running it.
then with x11 it can snoop on literally everything, sure, for a server linux is inherently more secure but as an end user i don't think it matters much.
9 times out of 10 the software you’re looking will typically land in your Distribution’s repository, before it lands in the main repository it’ll be vetted for stability and security in a testing repository.
If you want to install software outside your distributions repository you will need to vet the software yourself and make sure it’s compatible with your distro.