Zig and Go are serious. I think Python would be a language that isn't serious (despite it's widespread use in serious applications) but has a reputation for being easy. I don't know if that reputation is really deserved.
Anyway I would start with one of Python, Go or Typescript (via Deno). I would avoid Rust, Haskell, OCaml, C++ as your very first language, but they could be your second.
Whatever you do don't learn Python and stop there. That's the way to be a crap programmer. And if you do use Python learn to use type hints early on.