To answer these questions...
It's the same reason Overwatch and Rocket league are skipping the PS5, also the reason that the XseX is blowing past the PS5 in BC games, it's how it's done...
The Box's use a simple patch system to update a game to "new standards' the PSV on the other hand requires the system go into a PSPro like state where framerate can be unlocked, but actually doing a full update would require an actual new release...
https://www.pushsquare.com/news/2021/03/overwatch_skips_ps5_with_new_next-gen_upgrades
Do to this and limited resources, people etc, the PS5 version is a hassle while the Box version is simple...
this is why almost every PS5 enhanced game looks marginally better, because the bulk of the time they are simply using Pro assets...