I'm not sure systems programming is an exactly defined term. But maybe some of my projects qualify...
In my spare time, I'm working on a compiler (targeting wasm), which I am implementing in Rust. The (attempt at) generation of performant code taught me a lot about low-level stuff, as did the compiler itself.
I also started on a database, but it never got far, too many projects...
One that is technically an application but feels like systems programming: I'm doing a competition with some colleagues who can implement the fastest Voronoi image transform. Every allocation, instruction and indirection must be considered.
I only got into the low level stuff about 12-6 months ago, although I did some performance-critical stuff before that with numerical simulations.
My main language was Python for years, I never thought systems stuff was this interesting.