So I have played/developed, in FiveM for about 2-3 years. I have taken many breaks, to look into other platforms. And I have realized, how much power the client actually has. When I look at Roblox, which has no-anti-cheat(at least from what I know) - can run very smoothly, because the client has no power other than some small things, which is “needed”. Whereas in FiveM, modders can spawn vehicles, props, edit their health, and other things - directly from the client.
Now I know, that this may not be possible, and I am just spitting nonsense. I myself, know nothing about anything like this - but if it is possible, a anti-cheat may not be needed because the client has no power.
There are enough methods to prevent all of the things mentioned above. People simply aren’t aware of them nor does it seem like they want to educate themselves further on it. Nor does the market help at all with people pushing out insecure code. If someone puts out a Roblox game with insecure code you have the same effect. Enough examples of people cheating there as well.
It’s impossible to do game logic on the server in a mod for an existing game because the game simply doesn’t run on the server, and since game code isn’t available this is also near-impossible to accomplish. Comparing to a scratch-made game on a custom engine is extremely unfair as such.
Similarly, even here, if you write your gameplay code correctly and set up the server-side code the right way - e.g. entity lockdown - clients can’t ‘spawn vehicles, props’ nor ‘edit their health’ if you handle tracking of damage server-side.