I've always used mobile data when playing the game and I don't get many crashes from there. I'd like to say that the majority of crashes are due to WiFi users although I don't have the information to prove it. I tried farming garden of fear multiple times throughout floor VII-IX for a strike talisman and I spent a while in there on auto with the team that Kulimar suggested and didn't have a single crash. Finally pulled a strike talisman from floor IX so now I can make with a second counterstrike character. As for the garden of fear, my m.o. was Eternity Eddie, Assassin Golden Son, Sentinel Corrupt Droid and an Assassin Axis Soldier.