This always with happens with silent self-insert protagonists, and it's why they don't work in JRPGs.
You have a pre-defined character, with a pre-defined look, in a pre-defined story, with a pre-defined playstyle with pre-defined cutscenes but he's silent so you can "relate to them" or "decide for yourself what their voice is". This makes no sense.
It's just a compromise between an actual character and a character entirely made by the player. In the former you can have a character with a unique personality and interesting interactions or dynamics with other characters (ala Luke fon Fabre from ToA or Joel from TLOU) or you can have a character that is entirely made by the player (like in Fallout or other tabletop-inspired games where you make a character, decide what their stats and skills are, decide what they say in dialogue, and so on).
The "silent protagonist" doesn't take advantage of either. You don't have an interesting character who develops or interacts with other characters, and at the same time you don't have the freedom of choice of a character made by the player. In the latter it actually makes sense that the protagonist is silent because the game is literally designed around building dozens, if not hundreds of potential characters, all of whom have tons of potential personalities and who the player ultimately controls in both action and dialogue, one or even several "voices" would have no way of fitting all of them. The "silent protagonist" is neither.
