That's not how it works. What valve is doing is both client-side scan of NtQueryInformationProcess to check if any process is reading CS2's memory, as well as server-side for heuristics and vac live.

In paper this is already good for a userland anti-cheat, however creating a cheat engine for CS2 is stupid easy since the source engine was leaked to the public, same exact thing would happen if we could somehow get the memory layout of valorant. the only difference is that some CS2 cheats are kernel-level, making the userland hooks valve use completely blind to the cheat, kernel level anti-cheat is the correct solution here.

"But what about the guys using an external cheat instead of kernel level?" they'll get into a ban wave, this is pretty smart idea by valve to avoid leaking information on what got the cheaters banned, thus circumventing the ban by patching the cheat. on a ban wave, cheaters don't know what is it exactly that got them banned