If you find that multitasking is slow on your iPhone or iPad, you might need to turn off the Accessibility Shortcut.
If you've got an iPhone8 or older or any iPad, you might sometimes notice a delay when you try to activate multitasking by double-pressing the Home button. This is likely due to the iOS Accessibility Shortcut, which lets you quickly access several accessibility features by triple-pressing the Home button. Because this feature uses the triple-press, iOS waits a moment for the third press before registering that it isn't coming and activating multitasking.
The solution to slow multitasking activation is to turn off Accessibility Shortcut completely. The good news is that this is easy to do.