How to make a Swamp-like biome generation?

Does anyone know how to change the generation of a custom biome to the generation of a swamp in the minecraft 1.18.2 version. I need the biome to be kind of "flooded", as in the picture below. In older versions of minecraft there was a SurfaceBuilder responsible for generating the surface, is there something similar in version 1.18.2? Or maybe you have ideas how you can achieve the swamp effect in another way?