Be cautious in attribution. On a different distro I had nvidia drivers installed and working. When they weren't working It would boot to a black screen under Wayland. Anyway sorted out nvidia with Wayland. Gameplay was decent but sometimes I'd get stutter in heavy detail map areas, but later I realized there was a missing meta driver package, installing that made the system aware of switching fully to the nvidia GPU and performance improved substantially.

Switching distros sometimes provides other drivers or driver versions, which can appear like it made your system faster, when it could be on par on the other OS if the right package components installed.

The whole correlation causation scenario

That huge difference cant be an optimized kernel. Must be graphics driver differences...A kernel cant double the fps you get. Maybe a few more frames but thats it. Perhaps cachy has proper drivers and you had poor drivers on the other one.