>Mind and matter exist.
No, according to Samkhya, the mind- the ego and the intellect along with everything that you can sense- is purely physical. The non-material/non-physical/non-causal component is called Purusha (which is poorly understood since we do not have many primary sources on this philosophy), this Purusha is poorly described as "consciousness". Samkhya already defines awareness/ego/consciousness as a physical thing, hence it cannot be associated with Purusha. Unfortunately we may not know what the true extent of this philosophy was.
But tl;dr, according to Samkhya-
-The Universe is physical
-Everything you can sense is physical
-Causal change is an illusion (perhaps an early version of eternalism)
-However there is a non-physical Purusha (probably allows for free will in an otherwise eternalistic Universe)
-Purusha is not well understood
Most of the sources that do talk about Samkhya are its opponents (like Buddhism and Jainism) who in all likelihood would want to obscure the Samkhya philosophy even further (since that would be in their best interest).