Ruby is already a functional programming language – you can pass functions to functions, return functions from functions, and make closures in Ruby already. You’re probably already using some functional programming concepts if you’ve done anything non-trivial in Ruby even if it didn’t register for you as “functional programming”.

If you want to do ML (current “AI”), you’d probably do best to learn some Python (PyTorch, TensorFlow, etc.) and maybe CUDA for lower-level control. (It’s basically C++ with extra features for running code on NVIDIA GPUs.) There might be Ruby wrappers for the underlying ML libraries, but I expect most resources you’ll find (e.g. StackOverflow answers) will assume you’re working with Python…

If you’re still interested in learning one of the languages you listed, you’ll get some educational benefits from exploring them but I don’t think you’re likely to get much practical benefit out of it for AI over Ruby. I learned a lot from exploring Clojure personally – I particularly liked the idea of identity as a series of values over time – but I don’t work in the JVM ecosystem, and so I haven’t actually done anything with the language in 10+ years… The concepts I learned from playing with it were more useful than the language itself to me.