Does that mean one day there might be ways to change a human's sex with the use of crispr and genetic engineering in laboratory, before or after a zygote is produced? That "male pregnancy" might be possible? That there might be neopenises that look, feel and function exactly like natural penises? Or neovaginas that look, feel and function exactly like natural vaginas?

Maybe in a very distant future it will be possible, I have no clue what progress will bring. But it' s not going to be possible within our lifetimes, so I don' t see why we should waste time on it now. Leave it to the people who will live when/if that becomes a real possibility.

Is there a reason why a neopenis that looks, feels, and functions exactly like natural penises can not be considered a real penis? Or a neovagina that looks, feels, and functions exactly like natural vaginas can not be considered a real vagina? Despite doing the same things?

If it' s created in a laboratory by humans instead of naturally occurring, then it will always be an artificial replacement, even if it does exactly the same things that a real penis/vagina does.

But as my first paragraph says, this is not what is happening right now given that neither "neopenises" nor "neovaginas" function/look like the real thing.

Wouldn't a laboratory meat that tastes, looks, feels and functions exactly like natural meat be considered real meat?

No, it would be laboratory-made meat. Even if it manages to do everything real meat does, it would still be an artificial approximation. A good one perhaps, but an approximation nonetheless.

Long story short: if one day we will manage to actually change sex (unlikely, but let' s say it will be done), the people who will do it will still be people who were born one way and then changed. If that is going to actually happen, there will probably be different standards when it comes to categorize people based on sex.