Depending on which game, and which month it is measured in, Linux and Windows have been on par or trading blows for performance. Last I saw the performance had swung back slightly in favour of Windows though (seemed they started fixing some of the issues they had).

When you think about it, it is kind of insane that Linux can match or outperform windows when it has an extra layer translating the system calls though. And for many of us, who don't play competitive twitchy shooters on a high level, the performance of gaming on Linux is perfectly adequate currently. I played Baldur's Gate 3 on Linux earlier this year for example, and it maxed out the frame rate of my monitor.

IIRC from some discord threads, some games already perform better on Linux than on Windows. We are getting there. The only moat left is kernel anti cheat for games like Battlefield. I’m just fine if those stay on windows actually.