??? Does the "not ecchi" part mean you want romance with it too?
If not, there are several popular supernatural manga. I saw Flat and xxxHolic on your list but didn't see these ones, so hopefully you haven't read them:
Natsume Yuujinchou
Mushishi
Kaya-chan wa Kowakunai
Hozuki no Reitetsu (this one's more comedy)
Nurarihyon no Mago (more action-focused but most of the charas are yokai)
Mayonaka no Occult Koumouin
Tactics by Kinoshita Sakura (this one is...kinda on hiatus? idak but I saw someone say that the author uploaded stuff on their Pixiv)
There are definitely a lot more, but these are popular ones that I didn't see them in your list and know largely focused on supernatural. All of them also have an anime if you're interested in watching them!
My bad, Kaya-chan doesn't have an anime! But the rest do (ik bc I've watched them lol)
A lot of supernatural stories have weird sexual undertones or straight up fan service so that's what i meant by ecchi, anyway THANK YOU FOR THE LONG LIST
Ohhh gotcha. If that's the case, Nurarihyon and Tactics kinda play with that too, but Nurarihyon definitely does it a lot more. Not to say Tactics doesn't, but Nurarihyon has all the hallmarks of a shounen manga.
Anything supernatural? Like where the supernatural stuff is the focus and it's actually interesting and not ecchi