Worked on an ocaml codebase for two years. My advice is: choose a different language. It's just not a great dev experience in general
I'm pretty sure it's "working on a codebase" that kills your soul, not the minutae of particular language choice.
I've considered trying it for Advent of Code this year.
(also: generally speaking the "core" of .NET is quite unlike most other products Microsoft puts out, so chances are you will be pleasantly surprised)