Do explain how in a game where there is no character customization at all other than name, and in which the MC has an extremely plot-relevant backstory, how the hell can the MC be "literally you"? Yes, you can choose what he does at certain times, and you can even name him after yourself if you want to, but is your mother's name Syla?
The MC even has personality regardless of your choices, there are certain things you can't even influence, its not like they only talk when you choose something to say. Calling the MC here a self-insert is like calling Shirou Emiya a self-insert.