A larger depth limit with more layers to the Overworld (like the deepslate layer)

I've already managed to change the height/depth limit (thanks to some MCreator users, which if anyone is searching for how to do this like I was, it's some json files in your MCreator project directory), which my depth limit is -512, but I don't understand how to add more layers. I'm trying to make it as if you are digging into the core of the Earth, with blocks that hurt you and set you on fire.

I tried with ore generation but it doesn't make a thorough layer with patches of deepslate. I would like caves and ores to spawn, but I don't care that much and would rather at least have the layers.

Anyone know how to do this? If you do, I would appreciate it if you could let me know. Thanks!