>>526866645
Oh boy, Petra stages are always rough.You might need to adjust your team specifically for that (Try Adrianne or Claire to prevent her def debuff, or Jiho to cleanse her taunt).

In general, I'd suggest being a little reserved with your fodder and focusing on fewer units that can get enough copies for Origin. Fodder is a big bottleneck early on and you wanna be able to get past sync 200 on your teams.

If nothing else works, get a whale friend and hire their units to beat the worst stages.