How would the engines be running differently? It’s quite literally the same Windows build of the game running on Wine/Proton.
The simpler explanation is that Windows is poorly optimized, and runs a ton of inefficient crap in the background that’s taking cycles away from the CPU and maybe even GPU.
The simpler explanation is that Windows is poorly optimized, and runs a ton of inefficient crap in the background that’s taking cycles away from the CPU and maybe even GPU.