Materialism assumes matter exists in the absence of consciousness. The problem is we have no evidence of such matter.

How would you describe this 'matter' without using a mathematical model which originated in perceptual experience?

Note that the 2022 Nobel prize winner in physics, Anton Zeilinger, made this same point: We don't have any direct knowledge of some standalone, non conscious stuff we label "matter" - it is an abstract concept derived from experience.