There's a difference between having an adequate call to adventure, and being a 'chosen one'. Chosen one narratives are generally trite and tired, and I don't advocate for them as a staple - I actually kind of hate them, but that's only at a personal character level, and not relevant.

In a video game, you can give a call to adventure that is sufficiently pressing enough to push the main character into the leadership position; in an ideal situation it would be something that does not depend on the character being particularly charismatic or forceful of personality (because your character may not be), and it should be something independent of class, race, sex or background. This isn't typically difficult to do, and it does not require making the character into a super-special-divinely-mandated-chosen-one.

If you're going to have a collection of companions available for the player to take with them, or as options to pick from for playing, and they'll all be available right away at the beginning of the game, then this reason Must present itself in some tangible way at or before the time of the party forming up and choosing to follow the main character - otherwise you're left with the dissonance of the npcs following the pc for no reason beyond the out-of-character meta of their mechanical need to do so. If you don't want to present the real reason right away, then you need to present stop-gap reasons that justify it short term until your story is ready to present the true reason. Otherwise you have narrative dissonance and broken immersion.

Other games - even the games that Robert suggested, all do this correctly. To my personal experience, all of the fantasy RPGs I've played have presented some amount of internal justification for this, because that's simply a part of telling a coherent story. And to answer neprostoman, No - BG3 currently does not, and it does not even TRY to; it does nothing of the sort at all, not even broad or rough strokes. It literally does not. It leaves us at "They follow us because we are the PC and they are NPCs" meta-game mechanic and it seems satisfied for the majority of the first act to leave it at that. That's not good enough. Act 1 needs to present at least A reason for the player character being the leader and decision-maker, before or by the time important and/or powerful people start following our decisions, in order to preserve immersion and prevent dissonance.

It could do this with the tadpole, if they wanted to; It could, with a little more lore added in in some way to push our character into the leading role - and it could be done with a little bit of extra lore that pushes our character into the leading role no matter which character, custom or origin, we decide to play... but the game Does Not Do This.