Anything 6000 C30 or close to it, on the motherboard's QVL is a bonus. If you're interested in so-called "future proofing" I'd suggest you get a 48GB or 64GB kit, unless the difference means you don't buy the X3D, in which case get the X3D and 32GB.
Note that the X3D is less memory sensitive than non-X3D CPUs, i.e. it doesn't care unless your RAM is reaaaaaaaally slow.