> I wish there were a simpler language, like Rust (no garbage collector, no runtime), but that was a little more helpful and willing to do implicit things even if they are slightly slower than the most optimised code possible.

The fiddling with borrows isn't about being as optimised as possible, it's about being correct in the absence of garbage collection. Are you sure you need no GC and no runtime? Tasks like the script you describe sound like a perfect fit for something like OCaml.