I second LanX's suggestion to work through Higher Order Perl. It is an excellent level-up.

I'll add Rust to the list. The book is a great guide (and there are many other resources). I'd programmed C and C++ in college and several projects through the years, but never loved writing at that level until learning Rust. My big complaint is cargo and the way modules are handled, but once you get past that, the language itself is great. Interestingly, the "Maybe" monad example in linked by LanX is written in Rust.