Consider the matrices of the form $\left(\begin{smallmatrix}1&x\\\0&1\end{smallmatrix}\right)$, with $x\in(0,+\infty)$. All of them have determinant equal to $1$, but their norms are arbitrarily large. Does this answer your question?
Consider the matrices of the form $\left(\begin{smallmatrix}1&x\\\0&1\end{smallmatrix}\right)$, with $x\in(0,+\infty)$. All of them have determinant equal to $1$, but their norms are arbitrarily large. Does this answer your question?