Try paying attention to the UI hints. When part of the previous app shows up on the left of the screen, that’s when you’ll get the app switcher.
Here’s a decent video showing the principle: https://youtube.com/watch?v=ewhAR7BmoMM Note that he lets go when the UI hint shows up on the left, but no earlier.
The home button was one of the best widely-deployed pieces of UI in computing history, and they got rid of it.