Android 15 DP2 adds a swipe up feature on the Google Pixel Fold for transitioning apps seamlessly between screens

Swipe up to continue: Fold your phone and swipe up on the front display to continue using the app, or wait a few seconds for the screen to lock

That's an interesting option I might try, but I honestly think I'll set this to "never". I'm always happy when we have options on how to use our devices but for me personally closing the phone when I'm done using it is the most natural.