Also a quick tip for all yall who are not keen on long grinds. I had to use this trick during my first run of the game back on Vita and seems the process has been made a little easier with a mildly increased production rate in the Complete edition. There is an item known as a Tactician USB. It's a held item that boosts the amount of experience you earn in battle. These items stack and as Digimon Digivolve they can hold multiple items. Usually by Ultimate level they can hold three items. So if you have your active Digimon holding three each, you get a massive experience bump.
Obtaining them can be a bit time consuming but you can do a small shortcut of sorts. The best way to obtain them is to have a farm dedicated to the task. You'll need the farm to be level 2 at least and have the farm goods be Developer's Know-How (Which can be purchased in the shop at the Digilab for 25,000 yen each) in each slot. Next you'll want to fill that farm with Builder personality Digimon. Once you've done so, set them to develop items using the 1,000 Yen option. A full Builder line up should have a development time of 20 minutes. When the time is at about a minute, save the game. You can keep saving little by little to get right to the sweet spot of right before the development finishes. If the item produced isn't the USB, you can quickly soft reset to the main menu using the + button so to quit without saving. Reload the game and wait for development to end again. Rinse and repeat.
These items are crucial if you want to bulk up quick and bypass grinding by a significant amount.
I also recommend staying in the Digilab when the development is about to end but checking the produced item via the Digi Line message prompts. It's faster than activating the farm console as it will force you to take/sell the items, then back out with an overall longer process due to loading times and menu navigation.