I normally find turn-based combat really boring but I find Shin Megami Tensei games so engrossing in part due to the combat. You need to pay attention to mechanics and properly prepare for each boss fight if you want to overcome them. It’s not about just gathering enough exp. Do you know any games similar to SMT when it comes to gameplay?
tri-Ace games have fantastic combat mechanics, imo. Give the original Valkyrie Profile, any Star Ocean (later games have more intricate combat), or Resonance of Fate a spin.