I believe that all SoCs, not just those in the M2 family, will take advantage of the optimizations. As an example, this optimization showing the potential of MetalRT.I wonder if Apple will continue optimizing for M1 SoCs since the M2 is out. Will M2 optimizations work on M1 units?
This patch optimises subsurface intersection queries on MetalRT. [...] On M1 Max, with MetalRT selected, this can give a render speedup of 15-20% for scenes like Monster which make heavy use of subsurface scattering.
Blender Archive - developer.blender.org
developer.blender.org
By the way, it looks like Apple has gone back to Cycles optimizations after finishing the Metal backend for viewport.