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?
Just to add my opinion on this list:
The Etrian odyssey series is uniquely ds/3ds style gameplay with the touchscreen map that you must make yourself. Highly recommend.
Divinity: Original Sin 2 does turn based tactics better than any game I've ever played, and I've played so many. If you like heavy world building rpgs and turn based battles that are as developed as they come, you owe it to yourself to grab this one on sale. Also, d:os2 is the precursor game and engine that eventually spawned Baldurs gate 3. So there's that.
Bravely default and bravely second are both lightning in a bottle mixes of story telling and turn based combat. They are spiritual successors to the older final fantasy games by the same studio. The class/subclass system with the brave/default mechanic is absolutely sublime and unlike any other turn based game out there. Plus the story itself is amazing. Definitely worth picking up.
OK, that's all I wanted to say.