I don't know if this will be of interest, but I actually started my FP "journey" using O'Caml, oh (pun!) 10-15 years ago, but once I actually learned Haskell for real I didn't look back. There was just no contest. I've actually written a couple of pretty cool libraries for O'Caml that gained some traction in the community, way back when... which is a long-winded way of saying that I'm not a noob when it comes to O'Caml, so it's not that I don't understand what it can do for you :)

(I appreciate that people may have different requirements; mine were and are mostly around my own productivity -- not so much real-time/low-latency/predictable performance/etc.).