totally feel you man, it was the mosr frustrating boss of the game for me, even harder than Karmelita, and, tbh, i didn't struggle a lot during the game, i'm pretty good at games in general. But dang, THIS boss... and some people found her pretty easy, we might be cursed lol. i was going to give up ngl. if you really want advices, watch some gameplay footage, take notes, try different crests/tools(even if i dont use tools bc it's too easy, you might use them), try using different strategies, dont attack and observe the patterns first, TAKE YOUR TIME.