I need Tips from veterans

So i’ve been playing casually for about 2 months now and have recently hit a plateau. I can’t seem to get past battle 38 on campaign and don’t know where to go with my team!

My knowledge of the game is still fairly low as i barely know how to use gears and augments I need tips on which cards to rank up, focus on leveling up, lineups to use, characters i should get which packs i should go get ect ect?? All help would be appreciated🙏🙏