I played this game already but my knowledge of it is blurry. I'm hoping to get advice on what skills are the best. My priority is powering through the story, and raising 200 different types of digimon, and completing all collesium competitions
I don't have a clear memory of the game myself. Although, for what I remember, at the start, the ability to guard against attacks during battles is very important. In fact, guarding costs less order points compared to many skills while halving the damage taken (and later reducing it to 1HP lost). Couple that with buffing skill like Muscle Charge (if I am not mistaken), many enemies with their names displayed in red can be taken down.
Neglecting such great assets at the beginning is what makes life harder for many players who will then find themselves grinding more than they should.