Hypothetically--the PS4 version should be backwards compatible for PS5, similar to how other PS4 Atlus games are.
I'm guessing a majority of 25th is ports and rereleases of past mainline titles, with P3 getting a major rework to have FES and Female Protagonist content--alongside a graphical upscale on the same vain of P4G for PC. And the only "Major" title is either an ArcSys title, or a Spinoff.
It'll be the 15th anniversary of Persona 3, alongside the 25th Anniversary of Persona in general. I highly doubt P3 ain't gonna be addressed during this. Similar to FFVII, it is the most influential title in the series in the terms of kickstarting the general public's interest. And with P-Studio not involved with the SMT teams; that gives them a potential window to focus on a Persona 3 remake. They have assets from P3D that could be translated and adapted to cut costs and time if need too (as P3D/P5D was not made by an external partner).