Languages like Idris and Gleam are really niche and many of those I named aren't used commonly. If you're basically missing stuff from my last two bullet points, you're doing just fine. Yay for noticing Rust, I do think it's a nice language and a good investment but even that isn't yet mainstream. Some reassurance: if you find Rust difficult to get on with for a while, it's not just you, it's not as easy to pick up as many popular languages, though for good reasons and at least there's decent documentation.