Big Digimon vpet fan here and I hard disagree with saying this is just as unforgiving as the lcd pets. You dont have limited resources in those and can easily fight low level digimon over and over again to basically get guaranteed wins for your evo requirements. Plus all you really have to do besides that is feed and train them enough to keep them alive; there's WAY less to manage.
On paper, nothing you have to do in this game (train, manage weight, battle other players, etc.) is out of the ordinary, but it's the way those elements seem to fight each other and how constantly punishing failure is that's the problem. Training lowers weight which can lower other stats if it gets too low, but it also just lowers over time? You aren't given any freebies like the similarly too-hard-for-its-own-good Digimon World 1 to at least let you start over with a fighting chance. You can explore for random chances at resources, but NONE of the single player battles count for your win score. So other than the POSSIBLE monetary or item reward, you're risking having to decide between letting your Digimon die or using an incredibly expensive healing item if it loses. Again, in the original and more recent pets, injuries are free to treat. Every way you can fail or succeed consumes too many resources to get your foot in the door without 100% knowing what to do from the start and spending multiple doomed runs just to accumulate items to MAYBE raise ONE non-Numemon adult.
I've really wanted to like this game, especially with how they've talked about the roster and design choices. There's a lot of thought put into it! But I think it needs some major balance changes. I've been playing it for a good bit now, and every time I think I'm starting to understand what I've done wrong, it turns out there's way too much time consuming, random stuff to juggle.