I'm also teaching an OS class, and IMHO using some new shiny thing is not the right way to approach it, because the students will be put in an ideal imaginary world, and neither will face the real-world practice, nor understand how it all came to be the way it is now. I think, it may be a good follow-up course (like "System Programming in Rust") after the "normal" C-based course.

I also don't agree with the notion that other option is "to teach students to write C code riddled with security vulnerabilities, memory leaks, and race conditions". This is exactly what such kind of course should teach them not to do, clearly pointing these problems and explaining how to deal with them. But not having exposure to that in the learning environment will only make them repeat these mistakes in the real world.

Btw, I'm a Lisp programmer and not a C fan.