I don't remember much about the combat from the ds games other than the enemy ai could be cheesed by running around the perimeter of the battle arena while waiting for abilities/geos to cool down. If they had a better ai or higher difficulty I would take any of the combat options though!

Edit: found old ds and first game, played for a bit and the combat is alright, would definitely benefit from a lock onto enemy feature, and better enemy ai. The circling the perimeter works even better than I remember and allows for easy battles. The movement in combat also has some drift to it which I remember disliking alot back in the day. Also the using geos as an ultimate weapon in battle is still satisfying, upon using one you get a sick cut scene of the ultimate spectrobes you used and brings back lots of memories of using them in tough battles to turn the tide! Forgot about how you level 3 separate stats which each can add levels to the spectrobes which made building specific stat based spectrobes super engaging. Also the incubator rooms (4 of them!) allowed you to feed the minerals you excavated to the spectrobes. Also the excavation mini game is lightyears ahead of what pokemon implemented in Gen 4 and way more engaging! Using the ds mic to blow away debris brought a smile to my face all these years later. This honestly should have been the pokemon killer it was made out to be.