And now with Gleam moving past version 1.0 last year, the BEAM also boasts a decent amount of "flavors" of functional programming. You can go with Erlang/OTP (the alien tech that has been battle tested for almost 30 years), Elixir for it's great webdev ecosystem, Gleam if you like an ML-like programming language on the BEAM. LFE is also another great option if need a BEAM-native LISP.