Can you play games with two users at the same time?

The following:

We have a ps5 and a ps4.

On the ps4 we have two users and on the second we can also play the games from the first. At ps5 we only have the first one. Can I then play at the same time. Because it doesn't work with one user, but does it work with two users but the same game?

You can't play the same game with two users! Only the user who is using the PS4 or PS5 can play!