A 10/10 does not mean perfect or close to perfect. That game doesn't exist. Game development is extremely complex and it is impossible to make a perfect game, especially in a game of this size and this amount of content. 10/10 is for the few best AAA games in every genre. A master price. 1 / 10 is harder to define, but should be reserved for the absolute worst and unplayable games. 5 / 10 should be decent but quite meh.
A 10/10 literally means perfect, doesn't get any better than this and should be reserved for timeless masterpieces with almost no bugs, performance issues, half finished content and so on. Apart from that I think, it is really hard to rate BG3 fairly. It is definitely one of the most ambitious and complex games I have seen in a while and simple things like "no micro transactions" can't be rated high enough these days.
If I just rate the fun I actually have with it (I'm still discovering stuff in act 1), it is easily a 9/10. If I look at the raw quality of later acts, narrative structure, plot holes, unfinished quests, missing content and so on, it is more a 6/10. You recognize most problems the game has only, when you play it multiple times and compare it to what triggers or not for other players.
