Yeah seriously debilitate makes the fight so much easier since Trumpeter has no weaknesses and debilitate takes down all 3 stats instead of having to go through 3 rounds of debuffing.
I also had a party of Yukiko/Yosuke/Teddie since my Chie was built wrong and I'm not a big fan of Naoto. Teddie for attack/defense statups and yosuke for evasion, and I had a sp -50% on Yukiko.
I did have to level a lot for the final boss though, I believe I was around level 83 when I finally beat her second form. When I was lower, I wasted most of my sp on the first round and by the time I hit the 2nd form I was out of SP and just struggling to stay alive. And so I crafted a Trumpeter with mediaharan and leveled him up for debilitate and heat riser, made the fight 10 times easier.
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