I'd just like to chime in I really think being able to delete / exchange datas for species EXP is a great idea. I also have a very small collection of digimon I want to actually raise, because of the reborn mechanic, and that would be way more useful than ... anything else, I don't need two hundred individual digimon, lol.
Also agreeing that some of the rng is kind of whack / the time sink and age mechanic is really drawn out. I don't want it to go by super fast but I've spent literal HOURS playing and my digimon is only age 1. It also took me a couple of hours to even, for instance, get the golden acorns to even open challenges, leaving me just... stuck for a while. Extreme RNG dependency is meh.