However, it's always good to learn more. I have a couple of suggestions:
1. Rust. The Rust book is an excellent introduction to lower-level programming languages, and also to more functional patterns. I went into it from a primarily JS/PHP, and it's been a wonderfully refreshing experience. And it's also been an excellent way to level-up my programming experience.
2. Embedded programming. Get yourself an Arduino or an ESP32, and make something that connects to the physical world. Lot's of fun. You can technically combined this with Rust, but I'd recommend sticking to C/C++ for embedded work (at least at first) because it's much better supported.
3. AWS / Kubernetes / Cloud computing. Managing large amounts of infrastructure on these platforms is an art unto itself. And it's worth learning if it's something you have an interest in. I'm not usually a "training" kind of guy, but I'd recommend doing some kind of course / using structured learning materials for this. Because there's so much tribal knowledge that needs to be acquired.