KoraL I don't think parallel dimensions come into play when you return to a younger version of yourself. We call those second-chancers or second lifers, I believe. Rather than having alternate souls and dimensions, it's based off game logic where you pretty much load a game from a checkpoint or saved file.
I mean, you can, but what's so interesting about reading about a bunch of souls gathering in an alternative society or universe? Unless the story is about this poor soul trying to find a way to take back his body, there really isn't much you can do with the alternative universe because it's pretty much the same isekai template. For example: I got transmigrated into another universe because someone took over my body, so now I'm either going to turn into an overpowered god to rule over this new universe, or I shall live a slow life without being bullied in my previous life! In which case, the whole "new universe" and "original soul" become redundant. It becomes isekai all over again. You are just replacing "run over by truck-kun and summoned to another world" with "someone just forced my soul out of my body, and my soul got transported into another world." But the outcome and story will be the same. Are you ever going to make use of the fact that your original body got taken from you, or are you just going to live a slow life in this new universe like half of the isekai slow life protagonists out there?
Now, if your story is about the poor soul trying to take back his body from this powerful ex-god/ex-martial artist or whatever, that would make for a different, original and interesting story. But if you do that, the whole "other universe" becomes redundant. You need a reason for why the soul doesn't want to simply live in the new universe and take back his body. Maybe those whose bodies get taken by transmigrators are forced into hell, and to escape eternal suffering, they must find a way to regain their bodies from these audacious transmigrators who rudely steal their bodies from them? In Dead Mount Death Play, the guy doesn't want to take his body back from the necromancer lord who took over because his life sucks, and he instead pleads with the necromancer lord to help place his soul in a robot (for now he's stuck inside a stuffed animal as a gag). Apparently he wants to be a robot.
If you want to rewrite lore, you have to make it interesting. Changing the lore is itself pointless unless you can write a fresh, interesting story with the changed lore, otherwise you might as well not bother. Unless you do something interesting with your pasta monster, why would anyone want to read about a pasta monster? Is he going to pasta-rape girls? Is he going to become a god of foods? Will he create a world of food (where all the plants and animals are pretty much food-based, like seas of soup, plant creatures with literal peashooters, takoyaki with tentacles)? Or maybe the pasta monster is a dungeon core that creates a food dungeon? Will he evolve into some new dish? What's so interesting about a pasta monster?