How to Speed Up Camaraderie?
The trick is simple: All you have to do is equip multiple cards of the same character into your deck. This will add their combined Camaraderie increase upon completing a mission.
It is important to note which version of the character the card is treated as, however. Because characters such as Vegeta Xeno, Vegeta SSGSS, and Vegeta all have separate Camaraderie levels. Which means you can’t load them all onto the same deck to increase the speed of growth, unless you bring 2 of each.
For best results, try to assign as many copies of the same character as possible. As of the time of writing this guide, I built a deck with 6 Piccolos on it, and noticed a dramatic increase in my Camaraderie growth after running a few missions!