HIP is essentially the same as CUDA, CK is not a language but a library, and assembly is basically used in the Nvidia ecosystem as well, in the form of PTX.

There is absolutely nothing out of the ordinary here. Yes, it's multiple languages, but not any more or any different than what you'd use on an Nvidia platform (except obviously for the assembly part -- AMD's ISA is different from PTX, but that's to be expected).