Any language that forces me into a new domain, whether by the goal it wants to solve, its paradigms, or environment, seems highly worth it.
P.s. try OCaml
BTW, I know there are plenty of people who wouldn’t consider that a vacation, and that’s fine, but they are different from me.
most learners eventually gravitate towards Real World OCaml https://dev.realworldocaml.org/ for additional learning.
Unfortunately, the learning resources for different domains out there isn’t as highly curated or prolific as, say, rust. If you do web dev like me, it takes a bit more work to find the tools and put them together. But the language itself lends itself well to systems level programming.
Fortunately, the forum is a great help.