Adding a few borrows and annotations is not "an optimization that complex"; use Arc at first but then find those bottlenecks via profiling then fix them.

Fix them if needed, the OP’s point is that for a lot of applications it is not needed.

For most cases you will still be comfortably in the JVM/golang performance window.

Rust is great language, fighting the borrow checker sucks, don’t do it if you don’t need to.