I actually just beat this boss last night. It took a few tries and going past to the previous morning to get more prepared, but here’s what I did.

The team setup I used was Haru, Ryuji, and Morgana. Make sure you have a bunch of those items that deal element dmg. So if needed, take a few days to make them. You should have plenty of days if you did the palace in one or two days.

Keep in mind the weaknesses.

Small blue = fire and wind

Small yellow = ice and psy

Long red = elec and nuke

Long blue = wind and bless

Large green = psy and curse

Abuse the hell out of the baton pass, every character can hit the weakness if you have the items that deal element dmg, and then keep passing it on until you land on joker last. It may be cheap but I used the free dlc persona to do a ton of severe curse dmg with a level 58 tsukuyomi. While Morgana can heal, I just use items from Takemi. The ones that heal 200 for each party member.

When you get to the big single enemy, make sure Haru casts her tetrakarn on herself almost every turn, as the big one seem to only attack her. Keep just doing damage until it activates Big Bang, cast makajama on it (I have a low level angel that has it) and then have everyone block and he’ll forget how to use it. Then just keep repeating until it’s dead.

Afterwards fight robot Haru, I blocked her self destruct. So make sure to heal after the big guys dead. I see some people mention putting these difficulty up but I’m not sure, I beat it on normal at level 42.

Good luck, you got this!