I think the situation is quite simple here: there is dissonance.
BG3 is a game with dark themes (turning into a monster, killing children, eating humanoids etc) but with a light aesthetic (super-saturated colours, exaggerated moves like the shove or jump action, and Disney-level talking squirrels).
Larian has perfectly centred the themes of a BG game but it is unable (or unwilling) to provide the appropriate (or fitting, cohesive or any other adjective) visual experience to complement them.
And, beware, I love the game. Still, I can't deny its problems.