It depends on when have you switched from those “normal” languages to functional, and where do you work now. Java 10 years ago is not Java nowadays, and not Kotlin. These modern languages influenced by advantages of functional languages, and you can even write thr most of your code in the functional style.

Our company has some codebase in Clojure and Haskell, and it was a huge headache to find a substitution for a Haskell engineer when they left. There are so few experts on the market. But of course, if you’re an American big tech company, you’ll find an engineer.

And I’m not saying to you “hey, switch to Kotlin!” Nope, if you’re enjoying what you’re doing and it brings you money — keep going. But the sad reality is that it’s much harder to find a job for a pure funcional coder.