PS4 to buy or not worth?

Tell me guys! I do not fumble at all yet in these consoles, as I stopped in development still on Dandy and Sege, sat only on the computers. But on the computer bored to play, want to sit or fall apart near the telly and play RPGashki or something.

So these are the questions.
I read that PS5 can run PS4 games

What about PS4 games in PS Now and PS Plus?
All PS4 games with backward compatibility included in PS Plus or PS Now will be available to run on PS5.

And if I buy a PS4 then ps5 games (new products) will be able to run on PS4.

There is no money for such an expensive pleasure as PS5.

So that's whether to buy a PS4