Please suggest some danmei like Card Room & The Earth is Online. I really liked the mystery solving aspect esp Card Room's Heart challenge section. It doesn't matter if the relationship is slow burn but it should be without any love rival drama and angst. I'd prefer the focus to be on the tasks and the relationship to be smooth & no nonsense. Also preferably MC & ML team up early on (fixed team) like in the card room & we get to see them solve things together.
I don’t know if this falls under the category of what you’re looking for, but maybe “I Wasn’t Born Lucky”? It’s horror, but the main character also has tasks to fulfill and mysteries to solve. It’s an entertaining read and is kind of similar to Card Room (I think I started reading them both at around the same time) if you can stomach the horror aspect.
Sha qing Black Butterfly Kill the Lights Criminal psychology Breaking the wind (i think that the name ,its new )
Insider. It's a horror mystery solving novel,translation is smooth and fast as well I think arc 1 and 2 are done
-To be a heartthrob in a horror movie: contrary to the description, it's not all fluff. There's alot more to the plot than you would think. -I wasn't born lucky: this one has a really smart MC and I think it falls into what you're looking for (even if it doesn't though, this one's really good and i recommend it anyway) (´ ꒳` )
>_> Tbh I feel that I wasn't Born Lucky should be renamed to Mc Won't Stop Harassing Ghosts lol. Still pretty great to read.
Meeting A Demonic Cultivator, Even God Cries - this one is super mystery that you won't expect that kind of ending. Mc here is a transmigrated law abiding citizen to a cultivation world and became a demonic cultivator, and then was transferred back to earth but with a twist. He was in a horror game where he need to win inorder to live.