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?
Since you've played P4, Persona Q might be a good on-ramp into Etrian Odyssey. It's essentially EO's gameplay with personas, characters and skills/spells from P3 and P4. Q2 has the P5 characters as well but only the Japanese voices (which is why I never got around to it).