I was about to mention these as well! To be fair, the “advanced” part was mainly about the schedule being 40-50 pages per week, but I found the language to be very accessible, and they are quite gripping. (The former is by 東野圭吾 and you can find a bit of a fan discussion in the autumn challenge thread.) The latter is by 森博嗣 and as a small warning there’s lots of computer stuff talk in it (from 25 years ago 
) so that might be a bit hard to digest, depending on your general interests. Also they are big bois of 400 and 500 pages each, so you’d be in for a long ride.
My Intermediate Book Club nomination ifの悲劇 (which rodan linked above) is much shorter, but I have not read it yet so cannot comment.
Something else I always wanted to read but never got around to is the Zenigata Heiji story collection, but it’s quite old so I don’t know how hard it is. The stories are about 30 pages each and are available for free (also on Bookwalker) so it’s not too costly to try out, at least.
Generally speaking, in order to find something of a specific genre, I like to look at the prizes that are awarded for that genre (Japan has a ton of those). Even if you don’t like the specific books, you will get a list of interesting authors which you can explore further.
These two look as if they are spot on: