How to disable gestures to switch apps on iOS

I play a lot of games. Some are online. One of those online games have lots of tapping involved. However, the gestures to close apps or switch apps that were introduced for the iPhone X make it so that I leave the game and get disconnected a lot. This makes me incredibly angry.

I know there’s a way to turn it off. I’ve done it before. However I can’t remember how to turn it off? Where’s the option to do that?