I see a lot of people has different opinions in this, so I'm going to survey which one is the majority, at least in this site.
Mine has to be Last Surprise from Persona 5 and The Battle For Everyone's Soul from Persona 3.
I love Rivers in the Desert from Persona 5, and Mass Destruction form Persona 3 or P3FES, either one
Last Surprise and Wiping all out for my fav. Battle Theme, and Our Beginning for best Boss Theme
I'll Face Myself and Battlefor Everyone's souls and Burn my Dread Remix
The battle for everyone's souls from p3
Favorite Boss Battle: Nyx Avatar
I’d Say The Battle For Everyone’s Soul from P3 and Time To Make History From P4 Golden
What do you think?