> Solvable maybe by having a separate Linux version of the game, but that's also more supported needed.
As someone who would play on Linux then, it doesn't sound like a solution at all. The separate version would just be filled with cheaters then, would almost be like an punishment for Linux users.
I do not mean separate as in separate matchmaking. Just separate ports of the game. So Linux users are not running the same Windows port of the game as Windows users, just under Proton.
That way you don't need a backdoor in the Windows version of the game for the weaker Linux anticheat that runs through Proton. You would just have a native Linux version of the game with native anticheat.
> I do not mean separate as in separate matchmaking [...] for the weaker Linux anticheat that runs through Proton
This is exactly the problem. Users connecting via Linux are more likely to be cheaters, since the anti-cheat is weaker on Linux, so in order to protect the user-base at large (Windows users), they don't allow Linux clients at all. Allow the less protected Linux clients to connect goes against the very change they did.
A game can start up native Linux binaries even when the game itself is running under Proton.
But EAC has a kernel driver and there's no real native way of doing that on Linux that's stable as Linux has no stable kernel API, and measured boot isn't widely adopted so a custom kernel can just lie to the anti-cheat module.
I really hope Valve work on this, whilst it would mean perhaps online play only run on SteamOS in an optional locked down mode, it's better than the status quo.
When you say that it would "almost be like a punishment for Linux users", I think you're wrong, because it literally would be a value add. There is something interesting about the fact that offering you 10% more value would be taken as a downgrade
What is the value add of letting Linux players play multiplayer, and all the cheaters for that particular game is concentrated on the Linux servers so Linux players end up playing with the cheaters, and the Windows players get cheat-free servers?