Looking for a 1.20 mod similar to old 1.2.5 mod mine-up

So recently I was designing my mod pack for 1.20 when i randomly remembered a really old mod called mine up that had a really cool gimmick. What it would do is add the nether under your overworld not as a dimension but as an actual part of your overworld. It replaced all bedrock with a really thick layer of obsidan that youd break through to access the nether. It was supposed to be used with another mod called gravity craft as it also add an inverted nether/overworld, I included a screen shot of the page you would be directed to when creating a world for clarity. What i was wondering is if there was a mod for 1.20 (or any modern version) that did what this mod did to the nether that physically puts it under your overworld instead of other mods ive found that just make it so the void tps you to the nether. If there isnt, is it possible to recreate a mod like this for modern versions or would it be to performance heavy for modern versions just due to how much the games changed and everything thats been added to the nether.