I'm by far more proficient in Haskell than any other language (half a decade professionally at this point), and in general I find that it really helps me manage complexity, which games bring in spades. Abstraction feels like it is key, and Haskell so far even has really allowed for nice abstraction.

I've mostly done some 2D stuff, at most using some fixed-function-pipeline-sort of things (blending.) I'm still early in my computer graphics journey, but the Haskell Vulkan bindings are good (there's even a Quake3 engine written with Haskell and Vulkan) so I figure starting with learning Vulkan will be a good starting point. I'm a CompE by education so I would really prefer to start low-level I think.