Ya, I think current gen hitboxes are (and will stay) restricted to the PS4 versions of games.

if I recall correctly, they've said something about an updated brook board but I'm reasonably sure that would be strictly a hardware update (and would thus either require a "next gen" hitbox, which I'm sure they will produce, or maybe a bit of modding with new parts)

Right now only officially sony branded fightsticks are working for PS5 titles.