The universe does not know or care about our laws and they are incomplete.
For example, we have no idea how consciousness works, so at this point we stop at "I don't know", rather than inventing explanations.
I don't know if consciousness is computable -- I suspect it isn't.
If it is not computable then we cannot come up with laws to explain it.
Or maybe the whole universe is computable but its kolmogorov complexity is larger than its information capacity.
I agree that the universe doesn't care how we approximate these laws, but only that they clearly exist.
If these laws exist, they are certainly not material, unless you redefine material, and that is why I am no longer a materialist :)
However, I don't think any materialist would deny laws of physics exist. We might say that how materials interact with each other is an intrinsic property of material itself, just as an electron behaves as though it has a certain mass.
What definition of material would you use that separates it from its laws?