Baldur's Gate 3 has clearly design its narrative to more so reflect actual D&D games. You are basically just another adventurer, in a world full of magic. The world is every bit as extraordinary and special as you are - if anything, you're the fish out of water. All the companions have their own background, agency, and goals, but the DM/narrative finds some common ground reason to get the party to travel together. No one in the party is specifically more special or the "chosen one". Struggling to trust one another and RPing through group issues is given much more importance - you see it quite a bit with all the popular D&D Shows (i.e. Critical Role). BG3 is a single player game that tries to give you a D&D table-top experience.
Except of course for the magical tadpole which only YOU (+support cast) can control because some deity took interest in you. Thats especially true when you play an origin character and not a custom one.
No, in BG3 you are exactly as much a chose one as in BG or other RPGs.
The difference is that while on other games you start low and slowly rise to the top in BG3 you already encounter things normal people speak of in awe and fear like mind flayers, demons, fully grown dragons, the underdark, etc. left and right. What usually would be "the stuff of legends" is just normal from level 1 on.
