I understood the sibling comment recommending Ocaml and to a lesser extent Borgo, but OP is looking for a high level functional programming language based on gi

I understood the sibling comment recommending Ocaml and to a lesser extent Borgo, but OP is looking for a high level functional programming language based on giving Gleam as the reference point. How does C# fit here. I do think the compilation speed and runtime is at least in the same ballpark, but C#, while a perfectly fine language, is definitely not a functional language in syntax or semantics.