“Me” as opposed to a hypothetical other person who differs but some very diluted generic difference?
I don’t think personal identity survive that kind of test. And if it does, then by a huge factor the overwhelming difference is which sperm generic shuffle and which ovum.
If we are going to get into all this stuff it’s not clear what counterfactuals are relevant. A slight change a long time ago and there are no humans at all. Surely that is more significant?
And of course, maybe nothing is contingent. Maybe the entire universe must necessarily be what it is. We don’t know if contingency exists.
(Someone is going to say we know that quantum mechanics is contingent. But we don’t know any of that. We only know it contingent on various assumptions. Of course, a world that has no contingency but looks like ours will be filled with scientists who think they discovered contingency. Bugs Bunny also thinks he has choices to make, but he’s just drawn that way. We don’t even know if we have a past. If you were created on second ago exactly as you are now, you’d think all the things about the past that you do now. No amount of evidence can prove there was a past. Or that the past was causal instead of a fortuitous coincidence.)