PS4 pro or PS5 to buy?

I am looking into exploring the PlayStation. Currently looking into the PS4 lineup only.

I have, however, been asking myself the following questions:

I am coming from the Xbox (Owning the Series X) and am aware that there are probably many redundant games. So wanted to know what games are there which I would only be able to explore on PlayStation?

AND:

Would it make sense to go directly to PS5, because it is backwards compatible with PS4?