There is no way to do it except for the cast. This is significant drawback of the idea to pass arrays in this way.
Here is a similar thread where the C rules are compared to the C++ rules. We could conclude from this comparison that the C rules are not so well designed, because your use case is valid but C doesn’t allow the implicit conversion. Another such example is conversion of T ** to T const * const *; this is safe but is not allowed by C.
Note that since n is not a constant expression, then int n, int (*arr)[n] does not have any added type safety compared to int n, int *arr. You still know the length (n), and it is still silent undefined behaviour to access out of bounds, and silent undefined behaviour to pass an array that is not actually length n.
This technique has more value in the case of passing non-VLA arrays , when the compiler must report if you pass a pointer to an array of the wrong length.