Have you ever tested Debian stable vs Debian sid? You’ll notice a clear performance difference. Why? Because Debian Stable has older packages that don’t include performance related patches found in the newer ones. This is basic knowledge.
Newer = more feature & performance related patches at the cost of stability.
Older = Stability & downstreamed security patches. This is how releases cycles work.
Just look at it in terms of kernel version.
Debian Stable by default is at what? Kernel 6.1.0 now?
Arch is at kernel 6.6.3.
If you follow the Linux Kernel news you’d know that there’s pretty huge optimizations between these, some of which directly impact gaming on wine & proton.
Then there’s Mesa :
Debian Stable, Mesa 22.3.6
Arch Linux, Mesa 23.2.1
Huge performance patches between these.