Not quite systems programming but this might give you some insight. Swift is memory efficient, and runs stable backend services. I've seen benchmarks showing that it's slightly more performant than typescript but twice as memory efficient (but not as efficient when it comes to memory management compared to Rust, C, and C++).

The other point I've seen is that its string library is slow and very accurate.

Besides that, the C-interop means you have quite a bit of flexibility in leveraging existing libraries.