I fully agree with @nojb and @crabs-can-code recommendations, but I think there are other two resources that are worth mentioning.
To learn the language itself, I find both John Whitington’s books quite good but maybe a bit slow paced if you have already some experience.
If you don’t mind studying it while studying algorithms and data structures the CS3110 course book “OCaml Programming: Correct + Efficient + Beautiful” is fantastic, and since 2021 also includes videos.