There's a scifi book I was reading a couple years ago that had this as a presence--models of people's personalities a la LLMs were a commodity, but they varied wildly in how accurate they were. Alphas were supposed to be 1-to-1 with the originating personality (to the point that they had legal protections? I can't remember), whereas gammas were used to menial things, like serving as a phone-menu style gatekeeper to the real person.
I can't for the life of me remember the name of the novel though... I'll have to go digging through my bookshelves later.
(Maybe Revelation Space, by Alistair Reynolds...?)
The idea of "recreating" historical personas in sci-fi is very old, and the issue with accuracy has also been raised early. One that comes to my mind in particular is this one from 1950s, although the artificial personality is technically not an AI (it's hosted in a human brain):
I can't for the life of me remember the name of the novel though... I'll have to go digging through my bookshelves later.
(Maybe Revelation Space, by Alistair Reynolds...?)