> I hoped that ruby4 maybe implements stuff that python has, like type annotations

Ruby has had type annotations and typecheckers for quite a while. Unfortunately (IMO) the annotations are not inlinine.

> or making the damn parens mandatory, but no.

A linter/formatter can give the effect of that (and tune it for where it is appropraite) whether or not the language has it, though there are good reasons Ruby does not in general.

> No parens, so never know if something is a method or, callable, or variable.

Method and local variable are the only possibilities (callables are either the value of local variables or the return value of method calls),