That's a very simplistic view of the architecture. Consoles in general have multiple CPU complexes and caches that do not straddle the boundary, and also multiple memory buses.
Are you referring to the multiple CCXs as different "NUMA" nodes? Because they aren't, they still share the same memory controller. There isn't a shared cache, true, and that does have performance implications but that doesn't make it NUMA.
If you can point to anything to support your NUMA claim that'd be highly interesting, but all the block charts & teardowns I can find show it's clearly UMA.
