I play on ps5.
My friends bought the game to play with me but they own ps4's.
First, i had to re download the ps4 version of the game on my ps5 to be able to play with them which is kind of annoying. But then all my character saved game were gone. I had to start over which is really annoying. Ideally i think it would be great if at least the characters saved data were shared between the ps4 and ps5 version of the same ps5 console. Also it would be even better if i could just use the ps5 version of the game to play with a ps4 console player.