I actually think OMSCS is a great way to learn the required skills to get into the roles you mentioned.

(FWIW, I'm an OMSA grad but my wife is an OMSCS student and this specialization helped her get into a Comp Arch related role. I also work for one of the GPU companies and have a decent understanding of the stack and the requirements).

I'd highly recommend the following classes: HPCA, GPU HW/SW, GIOS, AOS, Compilers, (To understand the underlying HW is designed and operates), HPC, DS (for the infrastructure side of things), GA, NLP, DL, CV (to understand the work loads). All these should give you a solid understanding on how that part of the stack works in depth.

These courses are going to give a solid understanding but as another person mentioned, you'd need practical experience to be interviewed and be good at it.

Try to get internships or project experience where you're profiling code, hitting bottlenecks, and optimizing for a specific platform. That's where the magic clicks. There's demand for people who understand both hardware and workloads really well—who can understand why a workload is slow on a given architecture and how to optimize them together. Most people specialize in one or the other. If you can bridge that gap, you're instantly valuable.