I think "too slow" is "too slow to onboard juniors", not "too slow in terms of performance".
Though I will note that the Rust compilation times were also far more painful than I'd expected – even the tiny (~5k sloc) app at hand would take what felt like a minute to recompute the red squigglies in my editor.
TS felt slow if it took 5-15sec, and Sorbet (for Ruby) was usually <3sec IIRC, so a minute+ was pretty bad.
Rust was in the realm of "just don't use this language if you have ADHD" since you really can't make progress without the compiler's exacting approval, and I'd constantly get distracted while waiting.
You can use cargo check for that, which is fast. It's only for running tests or the like that an actual build is required. Rust also has IDE integration via rust-analyzer, so the error-marking "squiggles" can be recomputed incrementally.
As someone that might be similarly diagnosed for the same reasons, your comment does make me more optimistic of achieving something significant in my life, though.