It's not necessarily that I'm looking to avoid "grimdark" content, either. The Malazan series is one I enjoy and it is plenty "grimdark."
Nor am I really bothered or repulsed by sex.
What I truly hate is books where the author seems so up their own ass about writing a Serious Novel that nothing is fun. There's no vibrancy and richness and enthusiasm radiating from the worldbuilding.
Malazan is so absorbing to me because you can tell Steven Erikson is absolutely OBSESSED with his world and characters and concepts and he writes things just because they're fucking cool. Sometimes it's "Wouldn't it be awesome if there was an army of giant undead wolves and they were in a war with an army of giant sapient velociraptors with swords for arms. Fuck yeah." And sometimes it's "What if there was a scungy guy who bickers with his wife like Miracle Max from the Princess Bride and sometimes his wife shapeshifts into thousands of spiders? Fuck yeah."
That series is basically the worst possible series to recommend to someone trying to get into adult SFF, since there is a lot of sexual violence (there is war happening and the impacts on civilians get a lot of focus) and also every book is like 1200 pages long, has over a dozen POV characters, and requires active note taking to comprehend. The author is an anthropologist and It Shows. I haven't moved on to the sixth book because I don't know if I have the space in my brain for it.
But despite the overall inaccessibility and the number of criticisms I could make, the Malazan series obviously came about because the author's brain worms Compelled him. You read these books and you're like "this guy probably can't carry on a regular conversation about anything except orc burial mounds." Steven Erikson has something deeply wrong with him and if he didn't write 200k words a year about it he would just die.
Books that exist because the author was Compelled By The Brain Worms are different. With many recently published novels, I get the impression that the author did only exactly as much worldbuilding as they thought would be sellable and marketable, and no more.
We don't like that. We like the brain worms.