Imagine that I'm standing in front of you and I hold up a picture of a wooden ship. I say, "this is the ship of Theseus." From that point on, when I refer to "the ship of Theseus," I am referring to this particular ship. It's a trivial designation because it doesn't need to be anything more. All this designation means in this context is, "this ship in particular."

I then hold up another picture of the same ship taken a day later. I say again, "this is the ship of Theseus a day later." Assuming that I'm not being deceptive, how would you respond to this? Would you insist that, "it can't be the same ship because nothing stays the same from moment to moment"? Or would you be like any normal human being and say, "yeah, I remember the ship from the other photo. Same ship, different day." If you would choose the former, which you seem to be arguing for, you're being overly pedantic.

If I say, "hand me my phone," you (presumably) don't need to think too hard on what I'm referring to. I might need to specify, "the black one in that corner," but you don't need to look up case law to establish whether or not I should call it this. It is implicit that when I say "my phone" in this context what I am referring to is, "that phone in particular," and is implicitly referring to an object that you would be able to similarly identify it as "my phone." Why we understand that phone in particular to be "my phone" is a completely different discussion and ultimately irrelevant. If I were to ask you to "hand me my phone," and you were to say, "how am I supposed to know what that means without detailing what you mean by 'my' and 'phone'?" you would be being overly pedantic. I would get annoyed and probably just grab it myself because the pedantry is irrelevant and unnecessary for the purposes of you handing me my phone. You'd be starting an argument for the sake of starting an argument and digressing from what was relevant, which is precisely what you're doing with the ship of Theseus.

Here's some base level reading material to help get you started on your trek out of pedantry:
https://en.wikipedia.org/wiki/Ship_of_Theseus
https://en.wikipedia.org/wiki/Identity_(philosophy)