Hey, I love this project ! I'm really, really enjoying it, but I do have a couple of suggestions / issues. I can't quite tell how the Age of a digimon progresses - It almost seems to be based on real-time days, which makes the base cap of 50 really excessive for a game with progression that moves as quick as this one does. Dropping the cap to a smaller number or adjusting how age is accumulated might help this feature a little, or even having a Digimon World style age progression where each stage of a digimon has a different age cap, and perhaps the age could progress in increments of fifteen minutes, or half hours? So baby 1 would have an age cap of 10, progressed in increments of 30 minutes, that's about 5 hours, or in 15 minutes it's about 2.5 hours. Dropping the cap to 5 changes those estimates to 2.5 and 1.25 hours, respectively.
Given the nature of the game being by save and not progressing or simulating (from what I can tell) when the game is closed, 1.25-2.5 active hours for a baby 1 or 2 stage is pretty forgiving. It would allow the ReBorn system to be utilized more often as a digimon grows, making it more of an active gameplay mechanic.
Some of the evolution requirements and recruitment requirements are also a little demanding and not super respectful of the player's time. 2k+ battles on just one digimon to digivolve is very steep. I do like the variance to the evolution requirements, and how specialized XP plays a role in quite a few of them. Keramon to Chrysalimon, for example, is about 1500 dark xp, which isn't too difficult to obtain by doing challenges.
Having an option to way to Devolve a digimon would also be really great to make a chosen digimon feel more like a partner, expanding the training options.
Some varied minigame types for training would also be nice, but I do like the 'hit the mark' kind of thing that isn't too demanding of focus, and isn't time consuming at all, so that's not a negative for me.
I deeply enjoy collecting eggs and trying to see what I get, and fighting wild digimon. Some of the battles feel slightly unbalanced, but I'm not well versed in that aspect so I can't weigh in too heavily, and the hitboxes for digital world items and fish can be a little finicky.
One last suggestion is additional care objects, like a wood/stone hot spring bath or a bed-type object that accelerates energy gain when a digimon uses it, a functional decor toilet that could be crafted by one of the crafters, or some additional toys or skins for the ball. The bed would also be a nice way to maybe add in a function to have a digimon get tired and need to sleep occasionally, the same way they get hungry or bored, though I'm not 100% certain how that should work or how long a digimon should be asleep for since the game doesn't simulate while closed.
Keep up the good work, and thank you for everything you've done with this project. All in all, I am enjoying it greatly as it is now, and look forward to additional updates!