I’ve seen a lot of ppl struggling with it (as did I) so here’s my team and some advice!
Spheres: OD boosting spheres like vesper and omni star
Attack sphere on thunder units
Guard, KO resist, and damage mitigation spheres on most units, especially Nyami because she’s weaker here
I spammed legatos UBB and used nimrah and Tev UBB to revive my units
I used tev DBB with wang mu
I used nimrah DBB with nabris for cyclone to revive units in a pinch and break through cottons angel idol effect at the end
Nyami for steam DBB
Maeri for quagmire DBB
Ukie for normal hit count boost (don’t use her UBB before the robots balls show up because it effects single attack and you can’t kill the two on the side)
I used one revive
All my units are omni 3+ with max bond in DBB and their DBB partners also have raised stats and spheres equipped to max damage