Here are some novel recommendations that are all on this site with all being pretty good and with no harem(harems suck😡). The MC is smart for each novel except the first one since that MC lazes around

Seoul Object Story(very cool, I really love this one, scp-like world)

The Villains pov (DEFINALY inspired by shadow slave)

I've Become the King of Villains in the Game (super inspired by LOTM, using sequences, basically LOTM / The Legendary Mechanic)

Dorothy’s Forbidden Grimoire (similar to the above, just inspired by LOTM still pretty good)

Pick Me Up! (I haven't read the novel but the manhwa is really good)

mmm nice

mmm nice

mmm nice

mmm nice

mmm nice

mmm nice

mmm nice

mmm nice

mmm nice