>>72586960I beat everything pretty rapidly and got stuck at Wagahai too yesterday up until 2 am, took a nice sleep and managed to get some pretty nice equipments (and finally learned how to dodge and use abilities properly). If you don't get tilted Wagahai is doable. For the bullet hell you can just stand in the back and run in the same circle as the attack, dodging if you want into the stream so you end up at the same position. There's also a nice distance where you can just stand there and the beams won't even hit you but it happened just once.
I usually ignore the knight and take the opportunity to beat the shit out of him if he's closer to her. The triple ball attack is not fully dodgeable so I end up dodging to the side and running up behind her and smack her a bunch like you do for Karasu and the big circle of balls you dodge into it and stick to her ass as much as the average Plusmate would.
Bring some heals, use abilities and you should be fine.
Redoing the stage is pretty tedious but it gets you the opportunity to level up or upgrade multiple times if you feel you're too weak. Goodluck!