This game 100% needs more changes, right now It's more brutal than even the most archaic Digimon games. All the problems compound in a way that makes the experience just bad.
*First the game needs a "safe" option to make money, every current option runs the risk of running into a Digimon battle you are unlikely to win
*Shops should always have the essential items like medicine stocked,if limited item is to be a thing, drivers do that well enough.
*This isn't really needed, but Life spans/periods between digivolution should really be longer, it's pretty much impossible to completely train a Digimon well if you are working under just a 24-hour clock(people got to sleep and stuff)
*Mission searches as said by the guy above need higher success rates, but I'll go further. There shouldn't be ANY blank results, given how valuable stamina as well as time is in this game, and the player should at the very least be reward a random low-teir item(like a regular meat) or 50 or so bits.
I enjoy this even despite it's faults, but it most certainly needs work.