If I delete Minecraft, will my worlds be gone (ps4)?

I have to uninstall Minecraft because of a bug, I bought it on a CD. Are my worlds gone when I reinstall it?

No.

Do I have to pay attention to that?

To be on the safe side, you could copy the saved data to a stick

If you go to the minecraft folder you will find all worlds as files

The game and the respective saves are usually stored separately on the Playstation 4.

So you can temporarily uninstall the big games to make room without having to start again in the future.

So that shouldn't be a problem.