Yes, but in philosophy and science, there's a theory called EMERGENCE, where complex systems (like the human body and brain) have properties that cannot be portrayed by its parts alone or in another configuration (cells and such). Like a bunch of metal and plastic lying around cannot do much of anything, but put it together in the right way and you get a flying airplane.

Life becomes ever more complex over time, so identity pertains to the whole rather than a collection of parts.

But the alternate universe 'you' doesn't have to be even remotely like you. In fact, it cannot be, because it is in an alternate universe and thus there has to be at least one thing different at absolute bare minimum. One of the most basic rules of physics- no two things can exist in the same space at the same time, and thus no two things can ever be the same. Even if you created a perfect 1:1 copy of something, it will exist in a different time period or location than the original and thus IMMEDIATELY become divergent the moment it is created and no longer be a perfect copy.

The multiverse blooms from the original, in an infinite expansion- but they are different dimensions of the same thing. If you pick one far out from the point of origin it will be wildly different, but if you choose two dimensions relatively close- they will be partially overlapped. Because it is not fully diverged, it shares most traits with its neighboring universe. The energy flow pattern that makes up your psyche and the biomass that makes up your physical being still exist in many universes. Yea- in infinity, it can also have ended up as a rock or a pool of water or whatever else. But in the universes where it was born and evolved just like you- but ended up as another creature entirely... it is nothing like YOU as you exist in this universe, but it is YOU in THAT universe.

It depends on what we consider to be oneself. If you can't feel being that person, are you them just because of similarity? And maybe even this sort of identity as a whole is an illusion and it's a feeling created by this biomass you mentioned that's similar to seeing objects as separate from each other and as separate entities because of how the brain developed and what cognitive functions it has.

But if other "me" are actually "me" I would prefer them over this one here. I can't even read a single thing of yours lately and sleep all the time instead. I could be a cute fluffy creature instead of this human.

Well it isn't similarity- because there is an infinite number of universes, so there is a universe out there in which I was born a giant flesh balloon that vomits cotton candy and breathes chlorine, lol. The other universe versions of a person in comparison to your current universe variant can be infinitely different from one another. Rather what makes it you is its role within that universe- because the universe itself is also wildly different.

You know, like a 'big' boob. C cups are big on a small woman, normal on an average woman and small on a large woman. The 'role' of the boob depends on the body/universe in which it is placed. Ds are average looking size on a large woman, so in the 'large woman universe' Ds are the alternate universe version of Cs in an 'average woman universe'. When talking about a whole ass living being- 'role' isn't their job or even what they do, but rather a little bit of everything. It isn't a specific personality, appearance, race, or job- its dependent on what makes that universe different from the base universe. So the other 'you' could be anything or act like anything. The other you could be a supervillainous cloud of psychic gas.

Because if it was a literal translation of whatever made up the same biomass you are made from, but in a different universe that would create a shit ton of confusion, because what happens if someone ate your grandma before your parents were born? That means you never happened in that universe, but the biomass is still there- so then whoever had the highest percentage of the biomass recycled into their own being would become the equivalent of you- but they'd already be someone else's equivalence... so then they'd have to be two people at the same time? That don't make sense. I just mentioned the biomass existing in both as an example that each universe should have an equivalent of 'you' whether its even a living creature or not, it isn't a direct translation of; this mass = that person.

But like, okay- in universe A a violent elephant kills potential predators to protect its herd. In universe B there are zebra in that area, not elephant- there are violent zebra that defend their herd in that universe... but they are only a fraction of the mass of an elephant, so two zebra were raised to be like this out of necessity to make up for the loss of bulk and power the elephant had in universe A? That would mean both zebra are universe Bs elephant from universe A. It would be two different entities in the alternate universe if that theory held true.