I hear your confusion. Trying to figure out what is you and what is not you.
I don't typically have that same problem. I know what is me and what is not me. I am me - my others are them. They are most definitely not-me. Although I accept at an intellectual level that all of these me's belong to one actual human being. So I own my me's as being me, even whilst experiencing the subjective knowing that they are not me.
I don't become other me's. There is only one me (me!). But other me's in me exist. And they are them, each with their own independent sense of 'me'. (Not me, but their own sense of me as in how I would call myself 'me' and you would call your experience of your own self 'me' too). So we typically don't experience that confusion between ourselves as you seem to.
That shifting of a sense of self, that being different me's would perhaps(?) be more typical of OSDD. Which is very similar to DID and not in any way lesser than it, and is a debilitating disorder all in itself.
I don't know at all. I am merely responding as best I can, with the knowledge that I have, which pretty much is that my experience of DID seems to be different to the experiences of self that you describe.
But please remember I am not the gold standard of DID and nor am I an expert. Like you I am simply doing the best I can to muddle through this quagmire called life.