I do agree that the story and character are at best mediocre.
In current times, the stories and character are superb, but over the history of RPG games in general? I would say again -- mediocre.
I grew up on Mass Effect and Dragon Age, so I may be looking through nostalgia, but the story, characters, and relationships of those series felt deeper and had such lasting impact.
One such relationship mechanic I loved was the "tempering" or "hardening". Like DA's Alistair.

BG3 has quite a lot of plot issues. And save for ShadowHeart and LaeZel (and even still, it's mediocre at best), character development is quite abysmal.
One glaring example I cannot stand is:
When recruiting Wyll & Karlach, in the same scene/night/moment, Wyll instantly gives up on hunting Karlach and they become BFFS for alltime. What? SH and LZ have a better arc. I mean, I mean stubbing my toe in a sharp corner has better arc than that.

Also, I don't fully agree that this gaming is all about sex -- but sex sells. It certainly doesn't hinder it being the now highest grossing crpg of all time, correct me if I'm wrong.
Alas, any day would I take fully realized relationships (both platonic and romantic) over nudity and sex scenes.