Perfect wouldn't be the word, more so highly compatible.. I don't think there's necessarily just one, Considering the amount of people across the world but we are some what limited to only what's in our immediate vacinity.
So it essentially lessens the chance that we meet that highly compactable person...but they would technically still exist out there, they are just unreachable, therefore for some it's non existent.
I want to say yes and no, especially since I technically have my one (even though we are not currently in a relationship anymore) we wouldnt have a child together and shared almost 13 years together now ongoing (as once a couple and currently as friends) if we weren't I guess. I find the concept weird itself to a degree cause I'm still a very solitary person generally and thrive better that way, I just don't want a romantic relationship, but with us it's always seemed automatic like we are suppose just be... But as a logical person it doesnt make sense in anyway.
Human compatibility is more complicated to others depending on the personal wants, fantasises and the stardard they put out there to be matched by another (whether it be realistic or not)
On a weird note, I remember being told something when I was younger something to do with birthmarks, about having the same birthmark as some else meaning in some way our souls are connected regardless of time and space (also heard your birthmark has a connection to how you died in a previously life but I take this sort of stuff with a cynical grain of salt lol)
Which always made me laugh, however oddly enough both me and 'my one' share the same colour and shape birthmark (which is funny cause we're different skin tones lol), but in different places, mine on my leg, his on his forehead. its weird coincidence if anything, but its an entertaining thought.