Unfortunately many of the more popular multiplayer games with anti-cheat tend to consider "made working on Linux" a bug rather than a feature. E.g. Easy Anti-Cheat and Unreal Engine both support Linux natively but Epic still doesn't want to allow it for their own game, Fortnite. https://x.com/TimSweeneyEpic/status/1490565925648715781
There are even games like Infinity Nikki with anti-cheat that allows the Steam Deck but specifically detects and blocks desktop Linux. You have to wonder if that gets them any real security since the method they use to detect the Deck is probably spoofable.
There is more nuance to the anti-cheat systems supporting Linux argument than "it supports it but they won't use it". Turning on Linux support does weaken the security posture of the anti-cheat system, so it's not simply a decision of "it works with Linux, but they won't do it". It is moreso a question of whether the security posture changes for the game with this platform support enabled meet the business requirements. It's not a surprise that games with high MTX revenue do not turn this on, as I imagine this would be the biggest concern with this weaker security posture.
One of the boons of console hardware is also the strict execution environment that is presented on the system. While this of course doesn't prevent all cheating behavior in online games, a large selling point of it as a platform to publishers is not only the market segment available, but the security aspects of the runtime environment.
I'm not familiar with what new changes Valve has been working on in the anti-cheat space but historically most major anti-cheat systems, such as Easy Anti-Cheat, already have long included a server-side anti-cheat component. The catch rate (and overall accuracy) with both is just always going to be higher than only going with one approach.
I think you're hitting on ideal vs. constrained wants (or, at least, that's how I've always referred to them). That is: what they want to be able to allow in itself vs. what they want to allow given the trade-offs with other wants.
E.g. "I'm going to go to the beach all day" and "I'm going to keep my job" are both likely the results of ideal type wants whereas "I'm going to go to my job today and then the beach tonight" would likely be the result of a constrained want.
