Originally Posted by Zandel

New whale missions still easy enough to clear, 6-5 comes close but with that new break mechanic it's not terrible.

Pretty much this. If it's too hard for some, then that's a prime indicator that you need to improve your girls; level, evo/bloom, equipment, affection/2nd affection, ampies. Don't forget about the new Promotion skills (1st turn ATK up is by far the best choice, a tanky unit with Taunt (and some form of Evade) can help ensure your stronger units don't die first).

Oh, and 6-5 is not advisable to just hit Start and ignore; make use of your Solar Blasts (try and reserve for the Ancient Pest exclusively since it adds a lot to the faint meter). Have one girl in the crew who can spawn solar shrine nodes on the map (Strawberry Candle, Nigella); having another who spawns healing nodes (Chocolate Cosmos, Lantana) can help (though usually it seems like 1-2 nodes spawn after the mid-boss Pest).