Sort of, I was in a similar position to you a month ago since there are so few high quality cave mods around. You can, as MCModded said, use structure blocks in a way that creates air pockets with things inside them although calling these square air structures biomes is just wrong, the other alternative takes a lot of maths, patience and procedure blocks. I recently made a mod called glowing mushroom biome, which using several multi hundred block procedures creates non flat walls/roofs, stops liquids flowing into it and spawns grass and mushrooms and stuff.
I mostly made this mod to challenge myself with the generation and I'm pretty happy with how it turned out. I can send you the workspace if you'd like to do something similar
What you also could do is use a custom block that generates in veins of one, and uses a /fill command to replace all the stone blocks around with a custom block. If you wanted to take this even further, you could have the block spawn a certain number of flying entities that would also convert blocks around them--that way the biome could spread down into more caves. Of course, you'd have to make them die after a little while so they don't spread infinitely.
unfortunately no because biomes are set using only x and z coordinates in the game's code
Structure Blocks. thats how in my mod Cavecraft: Cave Update there are custom caves,
Sort of, I was in a similar position to you a month ago since there are so few high quality cave mods around. You can, as MCModded said, use structure blocks in a way that creates air pockets with things inside them although calling these square air structures biomes is just wrong, the other alternative takes a lot of maths, patience and procedure blocks. I recently made a mod called glowing mushroom biome, which using several multi hundred block procedures creates non flat walls/roofs, stops liquids flowing into it and spawns grass and mushrooms and stuff.
https://mcreator.net/modification/64029/glowing-mushroom-biome
I mostly made this mod to challenge myself with the generation and I'm pretty happy with how it turned out. I can send you the workspace if you'd like to do something similar
What you also could do is use a custom block that generates in veins of one, and uses a /fill command to replace all the stone blocks around with a custom block. If you wanted to take this even further, you could have the block spawn a certain number of flying entities that would also convert blocks around them--that way the biome could spread down into more caves. Of course, you'd have to make them die after a little while so they don't spread infinitely.