From the viewpoint of the organization, remote works far better for Rust. The less errors need to be found, the better. For local the argument is the same, but the matter is of less urgency. Shorter feedback loops allow errors to be corrected sooner, local normally has the advantage there.
Neither are easily available. There are more C++ programmers in total.
It's easier to find people who had some exposure to C++, but that does not make it easier to find good C++ programmers.