Asymptotic relation between $n^2 (n-2\lfloor \frac{n}{2} \rfloor)$ and $2\lfloor \frac{n}{2} \rfloor$

Question

What is asymptotic relation between $n^2 (n-2\lfloor \frac{n}{2} \rfloor)$ and $2\lfloor \frac{n}{2} \rfloor$?

My attempt: let $\lfloor \frac{n}{2} \rfloor = n$. Then the equation comes down to $n^3 $ and $n$ in terms of order function. Therefore, $n^3 \in \Omega(n)$.

However, this is not correct.