Uploading this because every other video uses Modernia. I was stuck here for 1-2 weeks. Slowly upgraded various characters, but I think it was Collection and Overload that helped me clear. And RNG. Pray the enemies don't one-shot, and the boss doesn't keep jumping away. Equip is all Tier 9 with a few Tier 10. Skills are mostly Lv4 to 8. I think I also lowered the graphics settings just to ensure 60 FPS, because supposedly it boosts Red Hood's DPS significantly. This game is so buggy and imbalanced.
EN guides seem to recommend against using Rapunzel, but she's singlehandedly allowed me to clear many difficult stages. I was able to clear the stages after this, but now I'm stuck on 20-28.
I really hate the combat power system. My power is around 110k but it nerfs me down to 96k. F2P, btw. For some reason you cannot write F2P in your profile, in both EN nor JP. I'd like to emphasize again that the EN translations are REALLY, REALLY BAD. Not that I care anymore. The bad game design made me not care about the story anymore. Also, as soon as I wrote NIKKE in the video title, my JP description got locked.