Play Ps5 with iPad as screen?

So I have the new iPad Pro 2020 and also an adapter that I can connect to an HDMI cable. I would like to use that as a fallback option to play on with the Ps5. Or display the picture for the game. What do I need to make the HDMI signal visible on the iPad?
You can definitely use the iPad as a screen extension, I know that. Unfortunately, I can't find anything how to set the Ipad as the primary screen instead.

An hdmi to usb c adapter. Then it would have to go, but I don't know whether apple allows it

I have the adapter, but nothing happens when you connect it. No reaction at all and then I ask myself why the adapter is made when it is actually not usable 🤨 I guess there has to be an app or something with which you can make the signal visible

This is not possible because the iPad does not support HDMI input. It is not blocked by Apple either, the iPad is simply not able to do so. The correct interface on the mainboard is missing

Then apple blocked that you would see in a moment

The adapter is there to transfer the screen from the iPad to another screen, not the other way around

The iPad only supports one HDMI output, i.e. Only one image / audio signal to another device (monitor, etc.).

Accordingly, you can't use your iPad as a screen for the PS5.

I can also use it as a second PC screen, so HDMI input works

Really now?

Yes! Definitely. It only sucks when I want to use it as my primary screen.

Even works with Windows, that's why I don't understand