Comment by Hasnep

It seems like your main gripe is that writing the type annotations slows you down, so I'd be interested to know what you think of languages like OCaml, Elm, Gleam or Roc. These are languages which never (or almost never) require any type annotations because the compiler can always infer all the types. Most people using these languages tend to add type annotations to top-level functions anyway though.

It seems to me that this is equivalent to a language without a type checker that automatically generates a unit test for every line of your program that tests its type.