A strong type system doesn’t need to be necessarily slow. The fanciness of it is what may make it slower.
Haskell, Rust, Typescript, etc. with their fancy features have to do a lot more work than simpler type systems like Rescript, OCaml or Elm.
Like others have said, there must be other reasons why it is slower.
I think it is great to have a benchmark like you did, gives a deterministic path to comparing and diagnosing issues.