This page is locked, so I can't add the change myself.
The new steam big picture, that resembles the steamdeck has been replaced to the old one in Feb 1 2023 at least on steam beta. https://store.steampowered.com/oldnews/189167
The thing is you can use -oldbigpicture launch parameter in steam to switch to the old one. It's important to point this out since I'm very sure it will keep tthis launch parameter for a long time.