All the readers of this forum will have a legally approved name and several official numbers linked to legal systems (drivers licence, tax file, social security etc).
Those define who we are in a legal sense.
And then of course we identify with place and type of work and human relationships.
But those do not define who we are. They are merely externalities.
So do we have an unique identity in any cosmic sense?
Or are we largely interchangeable? If so, then we are a what rather than a who.
Is it difficult for humans to consider if they are a collective "what" because the human race does not have clear idea of how it fits into the greater scheme?
It is in human nature to fear what they don't understand. Once they walk into that wall, they turn around and return to the status-quo. I think that is where the difficulty stems from.
A scorner seeks wisdom, and finds it not: but knowledge is easy to him that understands. Proverbs 14:6
everything else in nature is considered a what. does being self aware xempt us from that? at what point did we start developing an identity? id consider most mammals to have "personality".
As far as I can recall, the earliest accounts of individual humans being important record the gods creating humans and/or appointing humans to particular roles.