Is there a way to add a second overworld dimension that uses a specific seed & NOT the same seed as the main overworld?

Basically the title. I'd like to create another overworld and add it as a custom dimension in my world. Is that is possible, how would one go about doing that, or where might a guide or video or something to help be located?

I've tried adding a dimension via datapack, but the ability to define a separate seed for other dimensions was apparently removed some time ago. I've also looked at other dimension mods like multiverse, but they are all stuck in older versions of MC or still pull the save's main seed to generate the world.

P.S.
Code I used in the datapack (It still used the default overall seed and not the specified one, it was a carbon copy of the main overworld):

{        
  "type": "minecraft:overworld",
  "generator": {
	"biome_source": {
	  "preset": "minecraft:overworld",
	  "type": "minecraft:multi_noise"
	},
	"seed": 6487992,
	"settings": "minecraft:overworld",
	"type": "minecraft:noise"
  }
}