This is not the same thing as is being asked. On the old phone, double clicking would bring up the app switcher and you’d swipe it away. Your video above shows the way to do this now. BUT..., in the past if an app froze, or if the phone froze, you could hold down the side button, and then when the turn off swipe option came up, you could hold down on the home button to force a respring of the app, or the phone. With no home button now, I cannot find a way to force a respring. Right now, it seems like the only way to get out of a freeze is to reboot the phone completely.