Can you use the keyboard on the laptop to play on the ps4?

So connect laptop and not separate keyboard with ps4 (with cable or without it doesn't matter)

or is there an app or website like on a mobile phone where you can control the entire playstation via mobile phone and see everything?

so with the app on the cell phone you can go to another room and play on the cell phone there too.

There's the PS Remote Play app. If your phone is compatible, you can play Ps4 on your phone. The console must always be on and both devices must be connected to the same WLAN.

Thank you but i wanted to connect my laptop and not my mobile phone.

You asked if there was an app for mobile phones. There was never any talk of a laptop.

I wrote like on the cell phone and not whether an app like the one on the cell phone is on the cell phone is now irrelevant

Where you can then control the entire playstation via mobile phone

What else should one understand?

No matter